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{{Short description|General-purpose programming language}}
<!-- {{Lead too short|date=March 2023}} -->
{{Use dmy dates|date=November 2021}}
{{Infobox programming language
| logo = Python-logo-notext.svg
| logo size = 121px
| paradigm = [[Multi-paradigm programming language|Multi-paradigm]]: [[Object-oriented programming|Object-oriented]],<ref>{{Cite web|title=General Python FAQ – Python 3.9.2 documentation|url=https://docs.python.org/3/faq/general.html#what-is-python|access-date=2021-03-28|website=docs.python.org|archive-date=24 October 2012|archive-url=https://web.archive.org/web/20121024164224/http://docs.python.org/faq/general.html#what-is-python|url-status=live}}</ref> [[Procedural programming|Procedural]] ([[Imperative programming|Imperative]]), [[Functional programming|Functional]], [[Structured programming|Structured]], [[Reflective programming|Reflective]]
| released = {{start date and age|1991|02|20|df=y}}<ref name="alt-sources-history">{{cite web |url=https://www.tuhs.org/Usenet/alt.sources/1991-February/001749.html |title=Python 0.9.1 part 01/21 |publisher=alt.sources archives |access-date=2021-08-11 |archive-date=11 August 2021 |archive-url=https://web.archive.org/web/20210811171015/https://www.tuhs.org/Usenet/alt.sources/1991-February/001749.html |url-status=live}}</ref>
| designer = [[Guido van Rossum]]
| developer = [[Python Software Foundation]]
| latest release version = {{wikidata|property|edit|P548=Q2804309|P348}}
| latest release date = {{start date and age|{{wikidata|qualifier|single|P548=Q2804309|P348|P577}}}}
| latest preview version = {{wikidata|property|edit|reference|P548=Q51930650|P348}}
| latest preview date = {{start date and age|{{wikidata|qualifier|single|P548=Q51930650|P348|P577}}}}
| typing = [[Duck typing|Duck]], [[Dynamic typing|Dynamic]], [[Strong and weak typing|Strong typing]];<ref>{{Cite web|title=Why is Python a dynamic language and also a strongly typed language |url=https://wiki.python.org/moin/Why%20is%20Python%20a%20dynamic%20language%20and%20also%20a%20strongly%20typed%20language|access-date=2021-01-27|website=Python Wiki |archive-date=14 March 2021|archive-url=https://web.archive.org/web/20210314173706/https://wiki.python.org/moin/Why%20is%20Python%20a%20dynamic%20language%20and%20also%20a%20strongly%20typed%20language|url-status=live}}</ref> [[Optional typing|Optional type annotations]] (since 3.5, but those hints are ignored, except with unofficial tools)<ref name="type_hint-PEP">{{cite web|url=https://www.python.org/dev/peps/pep-0483/|title=PEP 483 – The Theory of Type Hints|website=Python.org|access-date=14 June 2018|archive-date=14 June 2020|archive-url=https://web.archive.org/web/20200614153558/https://www.python.org/dev/peps/pep-0483/|url-status=live}}</ref>
| implementations = [[CPython]], [[PyPy]], [[Stackless Python]], [[MicroPython]], [[CircuitPython]], [[IronPython]], [[Jython]]
| operating system = [[Windows]], [[macOS]], [[Linux|Linux/UNIX]], [[Android (operating system)|Android]], Unix-like systems, BSD variants<ref>{{Cite web |title=test – Regression tests package for Python – Python 3.7.13 documentation |url=https://docs.python.org/3.7/library/test.html?highlight=android#test.support.is_android |access-date=2022-05-17 |website=docs.python.org |archive-date=17 May 2022 |archive-url=https://web.archive.org/web/20220517151240/https://docs.python.org/3.7/library/test.html?highlight=android#test.support.is_android |url-status=live }}</ref><ref>{{Cite web |title=platform – Access to underlying platform's identifying data – Python 3.10.4 documentation |url=https://docs.python.org/3/library/platform.html?highlight=android |access-date=2022-05-17 |website=docs.python.org |archive-date=17 May 2022 |archive-url=https://web.archive.org/web/20220517150826/https://docs.python.org/3/library/platform.html?highlight=android |url-status=live }}</ref> and a few other platforms<!-- used to support many, only few support latest 3.8+ --><ref>{{Cite web |title=Download Python for Other Platforms |url=https://www.python.org/download/other/ |access-date=2023-08-18 |website=Python.org |language=en}}</ref>
| license = [[Python Software Foundation License]]
| file ext = .py, .pyw, .pyz, <!-- Too much trivia?: (since 3.5), since 3.8 latest supported and Python 3.5.10 Sept. 5, 2020--><ref>{{cite web |url=https://www.python.org/dev/peps/pep-0441/ |last=Holth |first=Moore |date=30 March 2014 |access-date=12 November 2015 |title=PEP 0441 – Improving Python ZIP Application Support |archive-date=26 December 2018 |archive-url=https://web.archive.org/web/20181226141117/https://www.python.org/dev/peps/pep-0441/%20 |url-status=live}}</ref><br />
.pyi, .pyc, .pyd <!-- too much trivia: .pyo (prior to 3.5)<ref>File extension .pyo was removed in Python 3.5. See [https://www.python.org/dev/peps/pep-0488/ PEP 0488] {{Webarchive|url=https://web.archive.org/web/20200601133202/https://www.python.org/dev/peps/pep-0488/ |date=1 June 2020}}</ref> -->
| website = {{URL|https://www.python.org/|python.org}}
| dialects = [[Cython]], [[PyPy#RPython|RPython]], [[Bazel (software)|Starlark]]<ref>{{cite web|title=Starlark Language|url=https://docs.bazel.build/versions/master/skylark/language.html|access-date=25 May 2019|archive-date=15 June 2020|archive-url=https://web.archive.org/web/20200615140534/https://docs.bazel.build/versions/master/skylark/language.html|url-status=live}}</ref>
| influenced_by = [[ABC (programming language)|ABC]],<ref name="faq-created"/> [[Ada (programming language)|Ada]],<ref>{{cite web |url=http://archive.adaic.com/standards/83lrm/html/lrm-11-03.html#11.3 |title=Ada 83 Reference Manual (raise statement) |access-date=7 January 2020 |archive-date=22 October 2019 |archive-url=https://web.archive.org/web/20191022155758/http://archive.adaic.com/standards/83lrm/html/lrm-11-03.html#11.3 |url-status=live}}</ref> [[ALGOL 68]],<ref name="98-interview"/> <br>[[APL (programming language)|APL]],<ref name="python.org">{{cite web|url=https://docs.python.org/3/library/itertools.html|title=itertools – Functions creating iterators for efficient looping – Python 3.7.1 documentation|website=docs.python.org|access-date=22 November 2016|archive-date=14 June 2020|archive-url=https://web.archive.org/web/20200614153629/https://docs.python.org/3/library/itertools.html |quote=This module implements a number of iterator building blocks inspired by constructs from APL, Haskell, and SML. |url-status=live}}</ref> [[C (programming language)|C]],<ref name="AutoNT-1"/> [[C++]],<ref name="classmix"/> [[CLU (programming language)|CLU]],<ref name="effbot-call-by-object"/> [[Dylan (programming language)|Dylan]],<ref name="AutoNT-2"/> <br>[[Haskell]],<ref name="AutoNT-3"/><ref name="python.org"/> [[Icon (programming language)|Icon]],<ref name="AutoNT-4"/> [[Lisp (programming language)|Lisp]],<ref name="AutoNT-6"/> {{nowrap|<br>[[Modula-3]]}},{{r|98-interview}}<ref name="classmix" /> [[Perl]],<ref>{{cite web |title=re – Regular expression operations – Python 3.10.6 documentation |url=https://docs.python.org/3/library/re.html |website=docs.python.org |access-date=2022-09-06 |quote=This module provides regular expression matching operations similar to those found in Perl. |archive-date=18 July 2018 |archive-url=https://web.archive.org/web/20180718132241/https://docs.python.org/3/library/re.html |url-status=live }}</ref> [[Standard ML]]<ref name="python.org"/>
| influenced = [[Apache Groovy]], [[Boo (programming language)|Boo]], [[Cobra (programming language)|Cobra]], [[CoffeeScript]],<ref>{{Cite web|url=https://coffeescript.org/|title=CoffeeScript|website=coffeescript.org|access-date=3 July 2018|archive-date=12 June 2020|archive-url=https://web.archive.org/web/20200612100004/http://coffeescript.org/|url-status=live}}</ref> [[D (programming language)|D]], [[F Sharp (programming language)|F#]], [[Godot (game engine)#GDScript|GDScript]], [[Genie (programming language)|Genie]],<ref>{{cite web
|url=https://wiki.gnome.org/action/show/Projects/Genie
|title=The Genie Programming Language Tutorial
|access-date=28 February 2020
|archive-date=1 June 2020
|archive-url=https://web.archive.org/web/20200601133216/https://wiki.gnome.org/action/show/Projects/Genie
|url-status=live
}}</ref> [[Go (programming language)|Go]], [[JavaScript]],<ref>{{cite web
|title=Perl and Python influences in JavaScript
|date=24 February 2013
|website=www.2ality.com
|url=http://www.2ality.com/2013/02/javascript-influences.html
|access-date=15 May 2015
|archive-date=26 December 2018
|archive-url=https://web.archive.org/web/20181226141121/http://2ality.com/2013/02/javascript-influences.html%0A
|url-status=live
}}</ref><ref>{{cite web
|title=Chapter 3: The Nature of JavaScript; Influences
|last=Rauschmayer
|first=Axel
|website=O'Reilly, Speaking JavaScript
|url=http://speakingjs.com/es5/ch03.html
|access-date=15 May 2015
|archive-date=26 December 2018
|archive-url=https://web.archive.org/web/20181226141123/http://speakingjs.com/es5/ch03.html%0A
|url-status=live
}}</ref> [[Julia (programming language)|Julia]],<ref name=Julia/> [[Mojo (programming language)|Mojo]],<ref name="Mojo">{{Cite web |last=Krill |first=Paul |date=2023-05-04 |title=Mojo language marries Python and MLIR for AI development |url=https://www.infoworld.com/article/3695588/mojo-language-marries-python-and-mlir-for-ai-development.html |access-date=2023-05-05 |website=InfoWorld |language=en |archive-date=5 May 2023 |archive-url=https://web.archive.org/web/20230505064554/https://www.infoworld.com/article/3695588/mojo-language-marries-python-and-mlir-for-ai-development.html |url-status=live }}</ref> [[Nim (programming language)|Nim]], [[Ring (programming language)|Ring]],<ref name="The Ring programming language and other languages">{{cite web |url=http://ring-lang.sourceforge.net/doc1.6/introduction.html#ring-and-other-languages |title=Ring and other languages |author=Ring Team |date=4 December 2017 |work=ring-lang.net |publisher=[[ring-lang]] |access-date=4 December 2017 |archive-date=25 December 2018 |archive-url=https://web.archive.org/web/20181225175312/http://ring-lang.sourceforge.net/doc1.6/introduction.html#ring-and-other-languages |url-status=live}}</ref> [[Ruby (programming language)|Ruby]],<ref name="bini"/> [[Swift (programming language)|Swift]]<ref name="lattner2014">{{Cite web |url=http://nondot.org/sabre/ |title=Chris Lattner's Homepage |last=Lattner |first=Chris |date=3 June 2014 |access-date=3 June 2014 |publisher=Chris Lattner |quote=The Swift language is the product of tireless effort from a team of language experts, documentation gurus, compiler optimization ninjas, and an incredibly important internal dogfooding group who provided feedback to help refine and battle-test ideas. Of course, it also greatly benefited from the experiences hard-won by many other languages in the field, drawing ideas from Objective-C, Rust, Haskell, Ruby, Python, C#, CLU, and far too many others to list. |archive-date=25 December 2018 |archive-url=https://web.archive.org/web/20181225175312/http://nondot.org/sabre/ |url-status=live}}</ref>
<!-- Do not put in as there's also a pure Java implementation (Jython): | programming language = [[C (programming language)|C]] -->
| wikibooks = Python Programming
}}
'''Python''' is a [[High-level programming language|high-level]], [[general-purpose programming language]]. Its design philosophy emphasizes [[code readability]] with the use of [[off-side rule|significant indentation]].<ref name="AutoNT-7" />
Python is [[type system#DYNAMIC|dynamically typed]] and [[garbage collection (computer science)|garbage-collected]]. It supports multiple [[programming paradigm]]s, including [[structured programming|structured]] (particularly [[procedural programming|procedural]]), [[object-oriented programming|object-oriented]] and [[functional programming]]. It is often described as a "batteries included" language due to its comprehensive [[standard library]].<ref name="About" /><ref>{{Cite web|title=PEP 206 – Python Advanced Library|url=https://www.python.org/dev/peps/pep-0206/|url-status=live|archive-url=https://web.archive.org/web/20210505003659/https://www.python.org/dev/peps/pep-0206/|archive-date=5 May 2021|access-date=11 October 2021|website=Python.org}}</ref>
[[Guido van Rossum]] began working on Python in the late 1980s as a successor to the [[ABC (programming language)|ABC programming language]] and first released it in 1991 as Python 0.9.0.<ref>{{Cite web|last=Rossum|first=Guido Van|date=2009-01-20|title=The History of Python: A Brief Timeline of Python|url=https://python-history.blogspot.com/2009/01/brief-timeline-of-python.html|access-date=2021-03-05|website=The History of Python|archive-date=5 June 2020|archive-url=https://web.archive.org/web/20200605032200/https://python-history.blogspot.com/2009/01/brief-timeline-of-python.html|url-status=live}}</ref> Python 2.0 was released in 2000. Python 3.0, released in 2008, was a major revision not completely [[backward compatibility|backward-compatible]] with earlier versions. Python 2.7.18, released in 2020, was the last release of Python 2.<ref>{{Cite web|url=https://pythoninsider.blogspot.com/2020/04/python-2718-last-release-of-python-2.html|title= Python 2.7.18, the last release of Python 2|last=Peterson|first=Benjamin|date=20 April 2020|website=Python Insider|access-date=27 April 2020|archive-date=26 April 2020|archive-url=https://web.archive.org/web/20200426204118/https://pythoninsider.blogspot.com/2020/04/python-2718-last-release-of-python-2.html|url-status=live}}</ref>
Python consistently ranks as one of the most popular programming languages, and has gained widespread use in the [[machine learning]] community.<ref>{{Cite web |title=Stack Overflow Developer Survey 2022 |url=https://survey.stackoverflow.co/2022/ |access-date=2022-08-12 |website=Stack Overflow |language=en |archive-date=27 June 2022 |archive-url=https://web.archive.org/web/20220627175307/https://survey.stackoverflow.co/2022/ |url-status=live }}</ref><ref>{{Cite web|title=The State of Developer Ecosystem in 2020 Infographic|url=https://www.jetbrains.com/lp/devecosystem-2020/|access-date=2021-03-05|website=JetBrains: Developer Tools for Professionals and Teams|language=en|archive-date=1 March 2021|archive-url=https://web.archive.org/web/20210301062411/https://www.jetbrains.com/lp/devecosystem-2020/|url-status=live}}</ref><ref name=tiobecurrent>{{cite web |title=TIOBE Index |publisher=TIOBE |url=https://www.tiobe.com/tiobe-index/ |access-date=3 January 2023 |quote=The TIOBE Programming Community index is an indicator of the popularity of programming languages |archive-date=25 February 2018 |archive-url=https://web.archive.org/web/20180225101948/https://www.tiobe.com/tiobe-index/ |url-status=live }} Updated as required.</ref><ref>{{Cite web|title=PYPL PopularitY of Programming Language index|url=https://pypl.github.io/PYPL.html|access-date=2021-03-26|website=pypl.github.io|language=en|archive-date=14 March 2017|archive-url=https://web.archive.org/web/20170314232030/https://pypl.github.io/PYPL.html|url-status=live}}</ref>
==History==
[[File:Guido van Rossum OSCON 2006 cropped.png|thumb|150px|The designer of Python, [[Guido van Rossum]], at [[O'Reilly Open Source Convention|OSCON]] 2006]]
{{Main|History of Python}}
Python was conceived in the late 1980s<ref name="venners-interview-pt-1" /> by [[Guido van Rossum]] at [[Centrum Wiskunde & Informatica]] (CWI) in the [[Netherlands]] as a successor to the [[ABC (programming language)|ABC programming language]], which was inspired by [[SETL]],<ref name="AutoNT-12" /> capable of [[exception handling]] and interfacing with the [[Amoeba (operating system)|Amoeba]] operating system.<ref name="faq-created" /> Its implementation began in December 1989.<ref name="timeline-of-python" /> Van Rossum shouldered sole responsibility for the project, as the lead developer, until 12 July 2018, when he announced his "permanent vacation" from his responsibilities as Python's "[[benevolent dictator for life]]", a title the Python community bestowed upon him to reflect his long-term commitment as the project's chief decision-maker.<ref name="lj-bdfl-resignation" /> In January 2019, active Python core developers elected a five-member Steering Council to lead the project.<ref>{{cite web |title=PEP 8100 |url=https://www.python.org/dev/peps/pep-8100/ |publisher=Python Software Foundation |access-date=4 May 2019 |archive-date=4 June 2020 |archive-url=https://web.archive.org/web/20200604235027/https://www.python.org/dev/peps/pep-8100/ |url-status=live}}</ref><ref>{{Cite web|title=PEP 13 – Python Language Governance|url=https://www.python.org/dev/peps/pep-0013/|access-date=2021-08-25|website=Python.org|language=en|archive-date=27 May 2021|archive-url=https://web.archive.org/web/20210527000035/https://www.python.org/dev/peps/pep-0013/|url-status=live}}</ref>
Python 2.0 was released on 16 October 2000, with many major new features such as [[list comprehension]]s, [[cycle detection|cycle-detecting]] garbage collection, [[reference counting]], and [[Unicode]] support.<ref name="newin-2.0" /> Python 3.0, released on 3 December 2008, with many of its major features [[backporting|backported]] to Python 2.6.x<ref name="pep-3000" /> and 2.7.x. Releases of Python 3 include the <code>2to3</code> utility, which automates the translation of Python 2 code to Python 3.<ref>{{Cite web|title=2to3 – Automated Python 2 to 3 code translation|url=https://docs.python.org/3/library/2to3.html|access-date=2021-02-02|website=docs.python.org|archive-date=4 June 2020|archive-url=https://web.archive.org/web/20200604232823/https://docs.python.org/3/library/2to3.html|url-status=live}}</ref>
Python 2.7's [[end-of-life product|end-of-life]] was initially set for 2015, then postponed to 2020 out of concern that a large body of existing code could not easily be forward-ported to Python 3.<ref>{{cite web |url=https://legacy.python.org/dev/peps/pep-0373/ |title=PEP 373 – Python 2.7 Release Schedule |work=python.org |access-date=9 January 2017 |archive-date=19 May 2020 |archive-url=https://web.archive.org/web/20200519075520/https://legacy.python.org/dev/peps/pep-0373/ |url-status=live}}</ref><ref>{{cite web |url=https://www.python.org/dev/peps/pep-0466/ |title=PEP 466 – Network Security Enhancements for Python 2.7.x |work=python.org |access-date=9 January 2017 |archive-date=4 June 2020 |archive-url=https://web.archive.org/web/20200604232833/https://www.python.org/dev/peps/pep-0466/ |url-status=live}}</ref> No further security patches or other improvements will be released for it.<ref>{{Cite web|url=https://www.python.org/doc/sunset-python-2/|title=Sunsetting Python 2|website=Python.org|language=en|access-date=22 September 2019|archive-date=12 January 2020|archive-url=https://web.archive.org/web/20200112080903/https://www.python.org/doc/sunset-python-2/|url-status=live}}</ref><ref>{{Cite web|url=https://www.python.org/dev/peps/pep-0373/|title=PEP 373 – Python 2.7 Release Schedule|website=Python.org|language=en|access-date=22 September 2019|archive-date=13 January 2020|archive-url=https://web.archive.org/web/20200113033257/https://www.python.org/dev/peps/pep-0373/|url-status=live}}</ref> Currently only 3.8 and later are supported (2023 security issues were fixed in e.g. 3.7.17, the final 3.7.x release<ref>{{Cite web |title=Python Release Python 3.7.17 |url=https://www.python.org/downloads/release/python-3717/ |access-date=2023-08-18 |website=Python.org |language=en}}</ref>). While Python 2.7 and older is officially unsupported, a different unofficial Python implementation, [[PyPy]], continues to support Python 2, i.e. "2.7.18+" (plus 3.9 and 3.10), with the plus meaning (at least some) "[[backporting|backported]] security updates".<ref>{{Cite web |last=mattip |date=2023-12-25 |title=PyPy v7.3.14 release |url=https://www.pypy.org/posts/2023/12/pypy-v7314-release.html |access-date=2024-01-05 |website=PyPy |language=en}}</ref>
In 2021 (and again twice in 2022), security updates were expedited, since all Python versions were insecure (including 2.7<ref>{{Cite web|title=CVE-2021-3177 |url=https://access.redhat.com/security/cve/cve-2021-3177|access-date=2021-02-26|website=Red Hat Customer Portal |archive-date=6 March 2021|archive-url=https://web.archive.org/web/20210306183700/https://access.redhat.com/security/cve/cve-2021-3177|url-status=live}}</ref>) because of security issues leading to possible [[remote code execution]]<ref>{{Cite web|title= CVE-2021-3177|url=https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-3177|access-date=2021-02-26|website=CVE|archive-date=27 February 2021|archive-url=https://web.archive.org/web/20210227192918/https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-3177|url-status=live}}</ref> and [[cache poisoning|web-cache poisoning]].<ref>{{Cite web|title= CVE-2021-23336|url=https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-23336|access-date=2021-02-26|website=CVE|archive-date=24 February 2021|archive-url=https://web.archive.org/web/20210224160700/https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-23336|url-status=live}}</ref> In 2022, Python 3.10.4 and 3.9.12 were expedited<ref>{{Cite web |last=Langa |first=Łukasz |date=2022-03-24 |title= Python 3.10.4 and 3.9.12 are now available out of schedule |url=https://pythoninsider.blogspot.com/2022/03/python-3104-and-3912-are-now-available.html |access-date=2022-04-19 |website=Python Insider |archive-date=21 April 2022 |archive-url=https://web.archive.org/web/20220421205820/https://pythoninsider.blogspot.com/2022/03/python-3104-and-3912-are-now-available.html |url-status=live }}</ref> and 3.8.13, because of many security issues.<ref>{{Cite web |last=Langa |first=Łukasz |date=2022-03-16 |title= Python 3.10.3, 3.9.11, 3.8.13, and 3.7.13 are now available with security content |url=https://pythoninsider.blogspot.com/2022/03/python-3103-3911-3813-and-3713-are-now.html |access-date=2022-04-19 |website=Python Insider |archive-date=17 April 2022 |archive-url=https://web.archive.org/web/20220417215022/https://pythoninsider.blogspot.com/2022/03/python-3103-3911-3813-and-3713-are-now.html |url-status=live }}</ref> When Python 3.9.13 was released in May 2022, it was announced that the 3.9 series (joining the older series 3.8 and 3.7) would only receive security fixes in the future.<ref>{{Cite web |last=Langa |first=Łukasz |date=2022-05-17 |title= Python 3.9.13 is now available |url=https://pythoninsider.blogspot.com/2022/05/python-3913-is-now-available.html |access-date=2022-05-21 |website=Python Insider |archive-date=17 May 2022 |archive-url=https://web.archive.org/web/20220517173546/https://pythoninsider.blogspot.com/2022/05/python-3913-is-now-available.html |url-status=live }}</ref> On 7 September 2022, four new releases were made due to a potential [[denial-of-service attack]]: 3.10.7, 3.9.14, 3.8.14, and 3.7.14.<ref>{{Cite web |title= Python releases 3.10.7, 3.9.14, 3.8.14, and 3.7.14 are now available |work=Python Insider |first1=Łukasz |last1=Langa |date=7 September 2022 |access-date=16 September 2022 |url=https://pythoninsider.blogspot.com/2022/09/python-releases-3107-3914-3814-and-3714.html |archive-date=13 September 2022 |archive-url=https://web.archive.org/web/20220913001104/https://pythoninsider.blogspot.com/2022/09/python-releases-3107-3914-3814-and-3714.html |url-status=live }}</ref><ref>{{Cite web |title= CVE-2020-10735 |work=CVE |access-date=16 September 2022 |url=https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-10735 |archive-date=20 September 2022 |archive-url=https://web.archive.org/web/20220920170528/https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-10735 |url-status=live }}</ref>
{{As of|2023|10|post=,}} Python 3.12 is the stable release, and 3.12 and 3.11 are the only versions with active (as opposed to just security) support. Notable changes in 3.11 from 3.10 include increased program execution speed and improved error reporting.<ref>{{Cite web |title=Python 3.11 released [LWN.net] |author=corbet |work=lwn.net |date=24 October 2022 |access-date=15 November 2022 |url= https://lwn.net/Articles/912216/}}</ref>
Python 3.12 adds syntax (and in fact every Python since at least 3.5 adds some syntax) to the language, the new (soft) keyword <code>type</code> (recent releases have added a lot of typing support e.g. new type union operator in 3.10), and 3.11 for exception handling, and 3.10 the <code>match</code> and <code>case</code> (soft) keywords, for structural [[pattern matching]] statements. Python 3.12 also drops outdated modules and functionality, and future versions will too, see below in [[#Development|Development]] section.
Python 3.11 claims to be between 10 and 60% faster than Python 3.10, and Python 3.12 adds another 5% on top of that. It also has improved error messages, and many other changes.
{{As of|2023|June|27|since=y}}, Python 3.8 is the oldest supported version of Python (albeit in the 'security support' phase), due to Python 3.7 reaching [[end-of-life product|end-of-life]].<ref>{{Cite web |date=2023-08-10 |title=Python |url=https://endoflife.date/python |access-date=2023-08-15 |website=endoflife.date |language=en-US}}</ref>
==Design philosophy and features==
Python is a [[multi-paradigm programming language]]. [[Object-oriented programming]] and [[structured programming]] are fully supported, and many of their features support functional programming and [[aspect-oriented programming]] (including [[metaprogramming]]<ref name="AutoNT-13" /> and [[metaobject]]s).<ref name="AutoNT-14" /> Many other paradigms are supported via extensions, including [[design by contract]]<ref name="AutoNT-15" /><ref name="AutoNT-16" /> and [[logic programming]].<ref name="AutoNT-17" />
Python uses [[dynamic typing]] and a combination of [[reference counting]] and a cycle-detecting garbage collector for [[memory management]].<ref name="Reference_counting">{{Cite web |url=https://docs.python.org/extending/extending.html#reference-counts |title=Extending and Embedding the Python Interpreter: Reference Counts |publisher=Docs.python.org |language=en |access-date=5 June 2020 |quote=Since Python makes heavy use of <code>malloc()</code> and <code>free()</code>, it needs a strategy to avoid memory leaks as well as the use of freed memory. The chosen method is called ''reference counting''. |archive-date=18 October 2012 |archive-url=https://web.archive.org/web/20121018063230/http://docs.python.org/extending/extending.html#reference-counts |url-status=live}}</ref> It uses dynamic [[Name resolution (programming languages)|name resolution]] ([[late binding]]), which binds method and variable names during program execution.
Its design offers some support for functional programming in the [[Lisp (programming language)|Lisp]] tradition. It has {{codes|filter|map|reduce|d=and}} functions; [[list comprehension]]s, [[Associative array|dictionaries]], sets, and [[generator (computer programming)|generator]] expressions.<ref name="AutoNT-59"/> The standard library has two modules ({{codes|itertools}} and {{codes|functools}}) that implement functional tools borrowed from [[Haskell]] and [[Standard ML]].<ref name="AutoNT-18" />
Its core philosophy is summarized in the [[Zen of Python]] (PEP 20), which includes [[aphorism]]s such as:<ref name="PEP20" />
<!-- Note this isn't a full list, just some of the more significant aphorisms -->
* Beautiful is better than ugly.
* Explicit is better than implicit.
* Simple is better than complex.
* Complex is better than complicated.
* Readability counts.
However, Python features regularly violate these principles and received criticism for adding unnecessary language bloat.<ref name="Python-Changes-2014">{{cite web |url=https://learning-python.com/python-changes-2014-plus.html |title=Python Changes 2014+ |last=Lutz |first=Mark |date=January 2022 |website=Learning Python |access-date=2024-02-25}}</ref><ref name="Python-is-not-a-great-programming-language">{{cite web |url=https://gist.github.com/RobertAKARobin/a1cba47d62c009a378121398cc5477ea |title=Python is not a great programming language |last=Thomas |first=Robin |date=2023-05-03 |website=GitHub Gist |access-date=2024-02-25}}</ref> Responses to these criticisms are that the Zen of Python is a guideline rather than a rule.<ref name="Confusion-regarding-a-rule-in-the-Zen-of-Python">{{cite web |url=https://discuss.python.org/t/confusion-regarding-a-rule-in-the-zen-of-python/15927 |title=Confusion regarding a rule in The Zen of Python |author=<!--Not stated--> |date=2022-05-03 |website=Python Help - Discussions on Python.org |access-date=2024-02-25}}</ref> New features has been so controversial that Guido van Rossum resigned as Benevolent Dictator for Life following vitriol over the addition of the assignment expression operator in Python 3.8.<ref name="The-Most-Controversial-Python-Walrus-Operator">{{cite web |url=https://pythonsimplified.com/the-most-controversial-python-walrus-operator/ |title=The Most Controversial Python Walrus Operator |last=Ambi |first=Chetan |date=2021-07-04 |website=Python Simplified |access-date=2024-02-05}}</ref><ref name="The-Controversy-Behind-The-Walrus-Operator-in-Python">{{cite web |url=https://therenegadecoder.com/code/the-controversy-behind-the-walrus-operator-in-python/ |title=The Controversy Behind The Walrus Operator in Python |last=Grifski |first=Jeremy |date=2020-05-24 |website=The Renegade Coder |access-date=2024-02-25}}</ref>
Nevertheless, rather than building all of its functionality into its core, Python was designed to be highly [[Extensibility|extensible]] via modules. This compact modularity has made it particularly popular as a means of adding programmable interfaces to existing applications. Van Rossum's vision of a small core language with a large standard library and easily extensible interpreter stemmed from his frustrations with [[ABC (programming language)|ABC]], which espoused the opposite approach.<ref name="venners-interview-pt-1" />
Python claims to strive for a simpler, less-cluttered syntax and grammar while giving developers a choice in their coding methodology. In contrast to [[Perl]]'s "[[there is more than one way to do it]]" motto, Python embraces a "there should be one—and preferably only one—obvious way to do it." <!-- the "—" spacing here, although inconsistent with Wikipedia MOS, is quoted text and must be maintained as is; do not "correct" it --> philosophy.<ref name="PEP20" /> In practice, however, Python provides many ways to achieve the same task. There are, for example, at least three ways to format a string literal, with no certainty as to which one a programmer should use.<ref name="Python-String-Formatting-Best-Practices">{{cite web |url=https://realpython.com/python-string-formatting/ |title=Python String Formatting Best Practices |last=Bader |first=Dan |website=Real Python |access-date=2024-02-25}}</ref> [[Alex Martelli]], a [[Fellow]] at the [[Python Software Foundation]] and Python book author, wrote: "To describe something as 'clever' is ''not'' considered a compliment in the Python culture."<ref name="AutoNT-19" />
Python's developers usually strive to avoid [[premature optimization]] and reject patches to non-critical parts of the [[CPython]] reference implementation that would offer marginal increases in speed at the cost of clarity.<ref name="AutoNT-20" /> Execution speed can be improved by moving speed-critical functions to extension modules written in languages such as C, or by using a [[just-in-time compilation|just-in-time compiler]] like [[PyPy]]. It is also possible to [[#Cross-compilers to other languages|cross-compile to other languages]], but it either doesn't provide the full speed-up that might be expected, since Python is a very dynamic language, or a restricted subset of Python is compiled, and possibly semantics are slightly changed.<ref name=PyJL />
Python's developers aim for it to be fun to use. This is reflected in its name—a tribute to the British comedy group [[Monty Python]]<ref name="whyname" />—and in occasionally playful approaches to tutorials and reference materials, such as the use of the terms "spam" and "eggs" (a reference to [[Spam (Monty Python)|a Monty Python sketch]]) in examples, instead of the often-used [[foobar|"foo" and "bar"]].<ref>{{Cite web|url=https://insidetech.monster.com/training/articles/8114-15-ways-python-is-a-powerful-force-on-the-web|title=15 Ways Python Is a Powerful Force on the Web|access-date=3 July 2018|archive-date=11 May 2019|archive-url=https://web.archive.org/web/20190511065650/http://insidetech.monster.com/training/articles/8114-15-ways-python-is-a-powerful-force-on-the-web|url-status=dead}}</ref><ref>{{Cite web |title=pprint – Data pretty printer – Python 3.11.0 documentation |url=https://docs.python.org/3/library/pprint.html |access-date=2022-11-05 |website=docs.python.org |quote=stuff=['spam', 'eggs', 'lumberjack', 'knights', 'ni'] |archive-date=22 January 2021 |archive-url=https://web.archive.org/web/20210122224848/https://docs.python.org/3/library/pprint.html |url-status=live}}</ref>A common [[neologism]] in the Python community is ''pythonic'', which has a wide range of meanings related to program style. "Pythonic" code may use Python [[Programming idiom|idioms]] well, be natural or show fluency in the language, or conform with Python's minimalist philosophy and emphasis on readability. Code that is difficult to understand or reads like a rough transcription from another programming language is called ''unpythonic''.<ref>{{Cite web|url=https://towardsdatascience.com/how-to-be-pythonic-and-why-you-should-care-188d63a5037e|title=How to be Pythonic and why you should care|first=Robert|last=Clark|date=26 April 2019|website=Medium|access-date=20 January 2021|archive-date=13 August 2021|archive-url=https://web.archive.org/web/20210813194313/https://towardsdatascience.com/how-to-be-pythonic-and-why-you-should-care-188d63a5037e?gi=dd6bc15118b3|url-status=live}}</ref><ref>{{Cite web|url=https://docs.python-guide.org/writing/style|title=Code Style – The Hitchhiker's Guide to Python|website=docs.python-guide.org|access-date=20 January 2021|archive-date=27 January 2021|archive-url=https://web.archive.org/web/20210127154341/https://docs.python-guide.org/writing/style/|url-status=live}}</ref>
==Syntax and semantics==
{{Main|Python syntax and semantics}}
Python is meant to be an easily readable language. Its formatting is visually uncluttered and often uses English keywords where other languages use punctuation. Unlike many other languages, it does not use [[curly bracket programming language|curly brackets]] to delimit blocks, and semicolons after statements are allowed but rarely used. It has fewer syntactic exceptions and special cases than [[C (programming language)|C]] or [[Pascal (programming language)|Pascal]].<ref name="AutoNT-52" />
===Indentation===
{{Main|Python syntax and semantics#Indentation}}
Python uses [[whitespace character|whitespace]] indentation, rather than [[curly bracket programming language|curly brackets]] or keywords, to delimit [[block (programming)|blocks]]. An increase in indentation comes after certain statements; a decrease in indentation signifies the end of the current block.<ref name="AutoNT-53" /> Thus, the program's visual structure accurately represents its semantic structure.<ref name=guttag>{{Cite book |publisher=MIT Press |isbn=978-0-262-52962-4 |last=Guttag |first=John V. |title=Introduction to Computation and Programming Using Python: With Application to Understanding Data |date=12 August 2016}}</ref> This feature is sometimes termed the [[off-side rule]]. Some other languages use indentation this way; but in most, indentation has no semantic meaning. The recommended indent size is four spaces.<ref>{{Cite web|url=https://www.python.org/dev/peps/pep-0008/|title=PEP 8 – Style Guide for Python Code|website=Python.org|access-date=26 March 2019|archive-date=17 April 2019|archive-url=https://web.archive.org/web/20190417223549/https://www.python.org/dev/peps/pep-0008/|url-status=live}}</ref>
===Statements and control flow===
Python's [[statement (computer science)|statements]] include:
* The [[Assignment (computer science)|assignment]] statement, using a single equals sign <code>=</code>
* The <code>[[if-then-else|if]]</code> statement, which conditionally executes a block of code, along with <code>else</code> and <code>elif</code> (a contraction of else-if)
* The <code>[[Foreach#Python|for]]</code> statement, which iterates over an ''iterable'' object, capturing each element to a local variable for use by the attached block
* The <code>[[While loop#Python|while]]</code> statement, which executes a block of code as long as its condition is true
* The <code>[[Exception handling syntax#Python|try]]</code> statement, which allows exceptions raised in its attached code block to be caught and handled by <code>except</code> clauses (or new syntax <code>except*</code> in Python 3.11 for exception groups<ref>{{Cite web |title=8. Errors and Exceptions – Python 3.12.0a0 documentation |url=https://docs.python.org/3.11/tutorial/errors.html |access-date=2022-05-09 |website=docs.python.org |archive-date=9 May 2022 |archive-url=https://web.archive.org/web/20220509145745/https://docs.python.org/3.11/tutorial/errors.html |url-status=live }}</ref>); it also ensures that clean-up code in a <code>finally</code> block is always run regardless of how the block exits
* The <code>raise</code> statement, used to raise a specified exception or re-raise a caught exception
* The <code>class</code> statement, which executes a block of code and attaches its local namespace to a [[class (computer science)|class]], for use in object-oriented programming
* The <code>def</code> statement, which defines a [[function (computing)|function]] or [[method (computing)|method]]
* The <code>[[dispose pattern#Language constructs|with]]</code> statement, which encloses a code block within a context manager (for example, acquiring a [[lock (computer science)|lock]] before it is run, then releasing the lock; or opening and closing a [[Computer file|file]]), allowing [[resource acquisition is initialization|resource-acquisition-is-initialization]] (RAII)-like behavior and replacing a common try/finally idiom<ref>{{cite web|url=https://www.python.org/download/releases/2.5/highlights/|title=Highlights: Python 2.5|website=Python.org|access-date=20 March 2018|archive-date=4 August 2019|archive-url=https://web.archive.org/web/20190804120408/https://www.python.org/download/releases/2.5/highlights/|url-status=live}}</ref>
* The <code>[[break statement|break]]</code> statement, which exits a loop
* The <code>continue</code> statement, which skips the rest of the current iteration and continues with the next
* The <code>del</code> statement, which removes a variable—deleting the reference from the name to the value, and producing an error if the variable is referred to before it is redefined
* The <code>pass</code> statement, serving as a [[NOP (code)|NOP]], syntactically needed to create an empty code block
* The <code>[[assertion (programming)|assert]]</code> statement, used in debugging to check for conditions that should apply
* The <code>yield</code> statement, which returns a value from a [[generator (computer programming)#Python|generator]] function (and also an operator); used to implement [[coroutine]]s
* The <code>return</code> statement, used to return a value from a function
* The <code>[[include directive|import]]</code> and <code>from</code> statements, used to import modules whose functions or variables can be used in the current program
The assignment statement (<code>=</code>) binds a name as a [[pointer (computer programming)|reference]] to a separate, dynamically allocated [[object (computer science)|object]]. Variables may subsequently be rebound at any time to any object. In Python, a variable name is a generic reference holder without a fixed [[Type system|data type]]; however, it always refers to ''some'' object with a type. This is called [[dynamic type|dynamic typing]]—in contrast to [[statically-typed]] languages, where each variable may contain only a value of a certain type.
Python does not support [[tail call]] optimization or [[first-class continuations]], and, according to Van Rossum, it never will.<ref name="AutoNT-55" /><ref name="AutoNT-56" /> However, better support for [[coroutine]]-like functionality is provided by extending Python's [[generator (computer programming)|generators]].<ref name="AutoNT-57" /> Before 2.5, generators were [[lazy evaluation|lazy]] [[iterator]]s; data was passed unidirectionally out of the generator. From Python 2.5 on, it is possible to pass data back into a generator function; and from version 3.3, it can be passed through multiple stack levels.<ref name="AutoNT-58" />
===Expressions===
Python's [[expression (computer science)|expressions]] include:
* The <code>+</code>, <code>-</code>, and <code>*</code> operators for mathematical addition, subtraction, and multiplication are similar to other languages, but the behavior of division differs. There are two types of divisions in Python: [[floor division]] (or integer division) <code>//</code> and floating-point<code>/</code>division.<ref>{{cite web|title=division|url=https://docs.python.org|website=python.org|access-date=30 July 2014|archive-date=20 July 2006|archive-url=https://web.archive.org/web/20060720033244/http://docs.python.org/|url-status=live}}</ref> Python uses the <code>**</code> operator for exponentiation.
* Python uses the <code>+</code> operator for string concatenation. Python uses the <code>*</code> operator for duplicating a string a specified number of times.
* The <code>@</code> infix operator<!-- was introduced in Python 3.5-->. It is intended to be used by libraries such as [[NumPy]] for [[matrix multiplication]].<ref name=PEP465>{{cite web |title=PEP 0465 – A dedicated infix operator for matrix multiplication |url=https://www.python.org/dev/peps/pep-0465/ |website=python.org |access-date=1 January 2016 |archive-date=4 June 2020 |archive-url=https://web.archive.org/web/20200604224255/https://www.python.org/dev/peps/pep-0465/ |url-status=live}}</ref><ref name=Python3.5Changelog>{{cite web |title=Python 3.5.1 Release and Changelog |url=https://www.python.org/downloads/release/python-351/ |website=python.org |access-date=1 January 2016 |archive-date=14 May 2020 |archive-url=https://web.archive.org/web/20200514034938/https://www.python.org/downloads/release/python-351/ |url-status=live}}</ref>
* The syntax <code>:=</code>, called the "walrus operator", was introduced in Python 3.8. It assigns values to variables as part of a larger expression.<ref name=Python3.8Changelog>{{cite web |title=What's New in Python 3.8 |url=https://docs.python.org/3.8/whatsnew/3.8.html |access-date=14 October 2019 |archive-date=8 June 2020 |archive-url=https://web.archive.org/web/20200608124345/https://docs.python.org/3.8/whatsnew/3.8.html |url-status=live}}</ref>
* In Python, <code>==</code> compares by value. Python's <code>is</code> operator may be used to compare object identities (comparison by reference), and comparisons may be chained—for example, {{code|lang=python|code=a <= b <= c}}.
* Python uses <code>and</code>, <code>or</code>, and <code>not</code> as Boolean operators.
* Python has a type of expression called a ''[[list comprehension#Python|list comprehension]]'', as well as a more general expression called a ''[[generator (computer programming)|generator]] expression''.<ref name="AutoNT-59" />
* [[Anonymous function]]s are implemented using [[Lambda (programming)|lambda expressions]]; however, there may be only one expression in each body.
* Conditional expressions are written as {{code|lang=python|code=x if c else y}}<ref name="AutoNT-60" /> (different in order of operands from the <code>[[?:|c ? x : y]]</code> operator common to many other languages).
* Python makes a distinction between [[list (computer science)|lists]] and [[tuple]]s. Lists are written as {{code|lang=python|code=[1, 2, 3]}}, are mutable, and cannot be used as the keys of dictionaries (dictionary keys must be [[immutable]] in Python). Tuples, written as {{code|lang=python|code=(1, 2, 3)}}, are immutable and thus can be used as keys of dictionaries, provided all of the tuple's elements are immutable. The <code>+</code> operator can be used to concatenate two tuples, which does not directly modify their contents, but produces a new tuple containing the elements of both. Thus, given the variable <code>t</code> initially equal to {{code|lang=python|code=(1, 2, 3)}}, executing {{code|lang=python|code=t = t + (4, 5)}} first evaluates {{code|lang=python|code=t + (4, 5)}}, which yields {{code|lang=python|code=(1, 2, 3, 4, 5)}}, which is then assigned back to <code>t</code>—thereby effectively "modifying the contents" of <code>t</code> while conforming to the immutable nature of tuple objects. Parentheses are optional for tuples in unambiguous contexts.<ref>{{cite web|title=4. Built-in Types – Python 3.6.3rc1 documentation|url=https://docs.python.org/3/library/stdtypes.html#tuple|website=python.org|access-date=1 October 2017|archive-date=14 June 2020|archive-url=https://web.archive.org/web/20200614194325/https://docs.python.org/3/library/stdtypes.html#tuple|url-status=live}}</ref>
* Python features ''sequence unpacking'' where multiple expressions, each evaluating to anything that can be assigned (to a variable, writable property, etc.) are associated in an identical manner to that forming tuple literals—and, as a whole, are put on the left-hand side of the equal sign in an assignment statement. The statement expects an ''iterable'' object on the right-hand side of the equal sign that produces the same number of values as the provided writable expressions; when iterated through them, it assigns each of the produced values to the corresponding expression on the left.<ref>{{cite web|title=5.3. Tuples and Sequences – Python 3.7.1rc2 documentation|url=https://docs.python.org/3/tutorial/datastructures.html#tuples-and-sequences|website=python.org|access-date=17 October 2018|archive-date=10 June 2020|archive-url=https://web.archive.org/web/20200610050047/https://docs.python.org/3/tutorial/datastructures.html#tuples-and-sequences|url-status=live}}</ref>
* Python has a "string format" operator <code>%</code> that functions analogously to <code>[[printf format string|printf]]</code> format strings in C—e.g. {{code|2=python|1="spam=%s eggs=%d" % ("blah", 2)}} evaluates to <code>"spam=blah eggs=2"</code>. In Python 2.6+ and 3+, this was supplemented by the <code>format()</code> method of the <code>str</code> class, e.g. {{code|2=python|1="spam={0} eggs={1}".format("blah", 2)}}. Python 3.6 added "f-strings": {{code|2=python|1=spam = "blah"; eggs = 2; f'spam={spam} eggs={eggs}'}}.<ref name="pep-0498">{{cite web |title=PEP 498 – Literal String Interpolation |url=https://www.python.org/dev/peps/pep-0498/ |website=python.org |access-date=8 March 2017 |archive-date=15 June 2020 |archive-url=https://web.archive.org/web/20200615184141/https://www.python.org/dev/peps/pep-0498/ |url-status=live}}</ref>
* Strings in Python can be [[concatenation|concatenated]] by "adding" them (with the same operator as for adding integers and floats), e.g. {{code|2=python|1="spam" + "eggs"}} returns <code>"spameggs"</code>. If strings contain numbers, they are added as strings rather than integers, e.g. {{code|2=python|1="2" + "2"}} returns <code>"22"</code>.
* Python has various [[string literal]]s:
** Delimited by single or double quotes; unlike in [[Unix shell]]s, [[Perl]], and Perl-influenced languages, single and double quotes work the same. Both use the backslash (<code>\</code>) as an [[escape character]]. [[String interpolation]] became available in Python 3.6 as "formatted string literals".<ref name="pep-0498"/>
** Triple-quoted (beginning and ending with three single or double quotes), which may span multiple lines and function like [[here document]]s in shells, Perl, and [[Ruby (programming language)|Ruby]].
** [[Raw string]] varieties, denoted by prefixing the string literal with <code>r</code>. Escape sequences are not interpreted; hence raw strings are useful where literal backslashes are common, such as [[regular expression]]s and [[Microsoft Windows|Windows]]-style paths. (Compare "<code>@</code>-quoting" in [[C Sharp (programming language)|C#]].)
* Python has [[array index]] and [[array slicing]] expressions in lists, denoted as <code>a[key]</code>, {{code|lang=python|code=a[start:stop]}} or {{code|lang=python|code=a[start:stop:step]}}. Indexes are [[zero-based numbering|zero-based]], and negative indexes are relative to the end. Slices take elements from the ''start'' index up to, but not including, the ''stop'' index. The third slice parameter called ''step'' or ''stride'', allows elements to be skipped and reversed. Slice indexes may be omitted—for example, {{code|lang=python|code=a[:]}} returns a copy of the entire list. Each element of a slice is a [[shallow copy]].
In Python, a distinction between expressions and statements is rigidly enforced, in contrast to languages such as [[Common Lisp]], [[Scheme (programming language)|Scheme]], or [[Ruby (programming language)|Ruby]]. This leads to duplicating some functionality. For example:
* [[List comprehensions]] vs. <code>for</code>-loops
* [[Conditional (programming)|Conditional]] expressions vs. <code>if</code> blocks
* The <code>eval()</code> vs. <code>exec()</code> built-in functions (in Python 2, <code>exec</code> is a statement); the former is for expressions, the latter is for statements
Statements cannot be a part of an expression—so list and other comprehensions or [[Lambda (programming)|lambda expressions]], all being expressions, cannot contain statements. A particular case is that an assignment statement such as {{code|lang=python|code=a = 1}} cannot form part of the conditional expression of a conditional statement. This has the advantage of avoiding a classic C error of mistaking an assignment operator <code>=</code> for an equality operator <code>==</code> in conditions: {{code|lang=c|code=if (c = 1) { ... } }} is syntactically valid (but probably unintended) C code, but {{code|lang=python|code=if c = 1: ...}} causes a syntax error in Python.
===Methods===
[[Method (programming)|Methods]] on objects are [[function (programming)|functions]] attached to the object's class; the syntax {{code|lang=python|code=instance.method(argument)}} is, for normal methods and functions, [[syntactic sugar]] for {{code|lang=python|code=Class.method(instance, argument)}}. Python methods have an explicit <code>[[this (computer programming)|self]]</code> parameter to access [[instance data]], in contrast to the implicit self (or <code>this</code>) in some other object-oriented programming languages (e.g., [[C++]], Java, [[Objective-C]], [[Ruby (programming language)|Ruby]]).<ref name="AutoNT-61" /> Python also provides methods, often called ''dunder methods'' (due to their names beginning and ending with double-underscores), to allow user-defined classes to modify how they are handled by native operations including length, comparison, in [[arithmetic operations]] and type conversion.<ref>{{cite book |last1=Sweigart |first1=Al |title=Beyond the Basic Stuff with Python: Best Practices for Writing Clean Code |year=2020 |publisher=No Starch Press |isbn=978-1-59327-966-0 |page=322 |url=https://books.google.com/books?id=7GUKEAAAQBAJ&pg=PA322 |language=en |access-date=7 July 2021 |archive-date=13 August 2021 |archive-url=https://web.archive.org/web/20210813194312/https://books.google.com/books?id=7GUKEAAAQBAJ&pg=PA322 |url-status=live}}</ref>
===Typing===
[[File:Python 3. The standard type hierarchy-en.svg|thumb|The standard type hierarchy in Python 3]]
Python uses [[duck typing]] and has typed objects but untyped variable names. Type constraints are not checked at [[compile time]]; rather, operations on an object may fail, signifying that it is not of a suitable type. Despite being [[Type system#Dynamic type checking and runtime type information|dynamically typed]], Python is [[strong and weak typing|strongly typed]], forbidding operations that are not well-defined (for example, adding a number to a string) rather than silently attempting to make sense of them.
Python allows programmers to define their own types using [[class (computer science)|classes]], most often used for [[object-oriented programming]]. New [[object (computer science)|instances]] of classes are constructed by calling the class (for example, {{code|lang=python|code=SpamClass()}} or {{code|lang=python|code=EggsClass()}}), and the classes are instances of the [[metaclass]] <code>type</code> (itself an instance of itself), allowing metaprogramming and [[reflection (computer science)|reflection]].
Before version 3.0, Python had two kinds of classes (both using the same syntax): ''old-style'' and ''new-style'',<ref name="classy" /> current Python versions only support the semantics new style.
Python supports [[optional typing|optional type annotations]].<ref name="type_hint-PEP" /><ref>{{Cite web |title=PEP 484 – Type Hints {{!}} peps.python.org |url=https://peps.python.org/pep-0484/ |access-date=2023-11-29 |website=peps.python.org}}</ref> These annotations are not enforced by the language, but may be used by external tools such as mypy to catch errors.<ref>{{cite web |title=typing — Support for type hints |url=https://docs.python.org/3/library/typing.html |website=Python documentation |publisher=Python Software Foundation |access-date=22 December 2023}}</ref><ref>{{cite web |url=http://mypy-lang.org/ |title=mypy – Optional Static Typing for Python |access-date=28 January 2017 |archive-date=6 June 2020 |archive-url=https://web.archive.org/web/20200606192012/http://mypy-lang.org/ |url-status=live}}</ref> Mypy also supports a Python compiler called mypyc, which leverages type annotations for optimization.<ref>{{cite web |title=Introduction |url=https://mypyc.readthedocs.io/en/latest/introduction.html |website=mypyc.readthedocs.io |access-date=22 December 2023}}</ref>
{|class="wikitable"
|+ Summary of Python 3's built-in types
|-
! Type
! [[immutable object|Mutability]]
! Description
! Syntax examples
|-
| <code>bool</code>
| immutable
| [[Boolean value]]
| {{code|lang=python|True}}<br/>{{code|lang=python|False}}
|-
| <code>bytearray</code>
| mutable
| Sequence of [[byte]]s
| {{code|lang=python|bytearray(b'Some ASCII')}}<br/>{{code|lang=python|bytearray(b"Some ASCII")}}<br/>{{code|lang=python|bytearray([119, 105, 107, 105])}}
|-
| <code>bytes</code>
| immutable
| Sequence of bytes
| {{code|lang=python|b'Some ASCII'}}<br/>{{code|lang=python|b"Some ASCII"}}<br/>{{code|lang=python|bytes([119, 105, 107, 105])}}
|-
| <code>complex</code>
| immutable
| [[Complex number]] with real and imaginary parts
| {{code|lang=python|3+2.7j}}<br/>{{code|lang=python|3 + 2.7j}}
|-
| <code>dict</code>
| mutable
| [[Associative array]] (or dictionary) of key and value pairs; can contain mixed types (keys and values), keys must be a hashable type
| {{code|lang=python|{'key1': 1.0, 3: False}}}<br/>{{code|lang=python|{}}}
|-
| <code>types.EllipsisType</code>
| immutable
| An [[Ellipsis (programming operator)|ellipsis]] placeholder to be used as an index in [[NumPy]] arrays
| {{code|lang=python|...}}<br/>{{code|lang=python|Ellipsis}}
|-
| <code>float</code>
| immutable
| [[Double-precision floating-point format|Double-precision]] [[floating-point arithmetic|floating-point number]]. The precision is machine-dependent but in practice is generally implemented as a 64-bit [[IEEE 754]] number with 53 bits of precision.<ref>{{Cite web
|title=15. Floating Point Arithmetic: Issues and Limitations – Python 3.8.3 documentation
|url=https://docs.python.org/3.8/tutorial/floatingpoint.html#representation-error
|access-date=6 June 2020
|website=docs.python.org
|quote=Almost all machines today (November 2000) use IEEE-754 floating point arithmetic, and almost all platforms map Python floats to IEEE-754 "double precision".
|archive-date=6 June 2020
|archive-url=https://web.archive.org/web/20200606113842/https://docs.python.org/3.8/tutorial/floatingpoint.html#representation-error
|url-status=live
}}</ref>
|
{{code|lang=python|1.33333}}
|-
| <code>frozenset</code>
| immutable
| Unordered [[set (computer science)|set]], contains no duplicates; can contain mixed types, if hashable
| {{nobr|{{code|lang=python|frozenset([4.0, 'string', True])}}}}
|-
| <code>int</code>
| immutable
| [[Integer (computer science)|Integer]] of unlimited magnitude<ref name="pep0237" />
| {{code|lang=python|42}}
|-
| <code>list</code>
| mutable
| [[list (computer science)|List]], can contain mixed types
| {{code|lang=python|[4.0, 'string', True]}}<br/>{{code|lang=python|[]}}
|-
| <code>types.NoneType</code>
| immutable
| An object representing the absence of a value, often called [[null pointer|null]] in other languages
| {{code|lang=python|None}}
|-
| <code>types.NotImplementedType</code>
| immutable
| A placeholder that can be returned from [[Operator overloading|overloaded operators]] to indicate unsupported operand types.
| {{code|lang=python|NotImplemented}}
|-
| <code>range</code>
| immutable
| An ''immutable sequence'' of numbers commonly used for looping a specific number of times in <code>for</code> loops<ref>{{cite web |title=Built-in Types |url=https://docs.python.org/3/library/stdtypes.html#typesseq-range |access-date=3 October 2019 |archive-date=14 June 2020 |archive-url=https://web.archive.org/web/20200614194325/https://docs.python.org/3/library/stdtypes.html#typesseq-range |url-status=live}}</ref>
| {{code|lang=python|range(-1, 10)}}<br/>{{code|lang=python|range(10, -5, -2)}}
|-
| <code>set</code>
| mutable
| Unordered [[set (computer science)|set]], contains no duplicates; can contain mixed types, if hashable
| {{code|lang=python|{4.0, 'string', True}}}<br/>{{code|lang=python|set()}}
|-
| <code>str</code>
| immutable
| A [[string (computer science)|character string]]: sequence of Unicode codepoints
| {{code|lang=python|'Wikipedia'}}<br/>{{code|lang=python|"Wikipedia"}}<syntaxhighlight lang="python">"""Spanning
multiple
lines"""</syntaxhighlight><syntaxhighlight lang="python">
Spanning
multiple
lines
</syntaxhighlight>
|-
| <code>tuple</code>
| immutable
| Can contain mixed types
| {{code|lang=python|(4.0, 'string', True)}}<br/>{{code|lang=python|('single element',)}}<br/>{{code|lang=python|()}}
|}
===Arithmetic operations===
Python has the usual symbols for arithmetic operators (<code>+</code>, <code>-</code>, <code>*</code>, <code>/</code>), the floor division operator <code>//</code> and the [[modulo operation]] <code>%</code> (where the remainder can be negative, <!--unlike in C language depending on compiler,<ref>{{Cite web|url=https://stackoverflow.com/questions/11720656/modulo-operation-with-negative-numbers/42131603|title=c – Modulo operation with negative numbers|quote=Note that, in C89, whether the result round upward or downward is implementation-defined.|website=Stack Overflow|access-date=25 September 2019}}</ref>--> e.g. <code>4 % -3 == -2</code>). It also has <code>**</code> for [[exponentiation]], e.g. <code>5**3 == 125</code> and <code>9**0.5 == 3.0</code>, and a matrix‑multiplication operator <code>@</code> .<ref>{{cite web |url=https://legacy.python.org/dev/peps/pep-0465/ |title=PEP 465 – A dedicated infix operator for matrix multiplication |work=python.org |access-date=3 July 2018 |archive-date=29 May 2020 |archive-url=https://web.archive.org/web/20200529200310/https://legacy.python.org/dev/peps/pep-0465/ |url-status=live}}</ref> These operators work like in traditional math; with the same [[order of operations|precedence rules]], the operators [[Infix notation|infix]] (<code>+</code> and <code>-</code> can also be [[unary operation|unary]] to represent positive and negative numbers respectively).
The division between integers produces floating-point results. The behavior of division has changed significantly over time:<ref name="pep0238"/>
* Current Python (i.e. since 3.0) changed <code>/</code> to always be floating-point division, e.g. {{code|class=nowrap|2=python|1=5/2 == 2.5}}.
* The floor division <code>//</code> operator was introduced. So <code>7//3 == 2</code>, <code>-7//3 == -3</code>, <code>7.5//3 == 2.0</code> and <code>-7.5//3 == -3.0</code>. Adding {{code|class=nowrap|2=python2|1=from __future__ import division}} causes a module used in Python 2.7 to use Python 3.0 rules for division (see above).
In Python terms, <code>/</code> is ''true division'' (or simply ''division''), and <code>//</code> is ''floor division.'' <code>/</code> before version 3.0 is ''classic division''.<ref name="pep0238"/>
Rounding towards negative infinity, though different from most languages, adds consistency. For instance, it means that the equation {{code|class=nowrap|2=python|1=(a + b)//b == a//b + 1}} is always true. It also means that the equation {{code|class=nowrap|2=python|1=b*(a//b) + a%b == a}} is valid for both positive and negative values of <code>a</code>. However, maintaining the validity of this equation means that while the result of <code>a%b</code> is, as expected, in the [[half-open interval]] [0, ''b''), where <code>b</code> is a positive integer, it has to lie in the interval (''b'', 0] when <code>b</code> is negative.<ref name="AutoNT-62" />
Python provides a <code>round</code> function for [[rounding]] a float to the nearest integer. For [[Rounding#Tie-breaking|tie-breaking]], Python 3 uses [[round to even]]: <code>round(1.5)</code> and <code>round(2.5)</code> both produce <code>2</code>.<ref name="AutoNT-64" /> Versions before 3 used [[Rounding#Rounding away from zero|round-away-from-zero]]: <code>round(0.5)</code> is <code>1.0</code>, <code>round(-0.5)</code> is <code>−1.0</code>.<ref name="AutoNT-63" />
Python allows Boolean expressions with multiple equality relations in a manner that is consistent with general use in mathematics. For example, the expression <code>a < b < c</code> tests whether <code>a</code> is less than <code>b</code> and <code>b</code> is less than <code>c</code>.<ref name="AutoNT-65" /> C-derived languages interpret this expression differently: in C, the expression would first evaluate <code>a < b</code>, resulting in 0 or 1, and that result would then be compared with <code>c</code>.<ref name="CPL" />
Python uses [[arbitrary-precision arithmetic]] for all integer operations. The <code>Decimal</code> type/class in the <code>decimal</code> module provides [[decimal floating point|decimal floating-point numbers]] to a pre-defined arbitrary precision and several rounding modes.<ref name="AutoNT-88"/> The <code>Fraction</code> class in the <code>fractions</code> module provides arbitrary precision for [[rational number]]s.<ref>{{cite web|title=What's New in Python 2.6 |url=https://docs.python.org/2.6/whatsnew/2.6.html|website=Python v2.6.9 documentation |date=Oct 29, 2013 |access-date=26 September 2015|archive-date=23 December 2019|archive-url=https://web.archive.org/web/20191223213856/https://docs.python.org/2.6/whatsnew/2.6.html|url-status=live}}</ref>
Due to Python's extensive mathematics library, and the third-party library [[NumPy]] that further extends the native capabilities, it is frequently used as a scientific scripting language to aid in problems such as numerical data processing and manipulation.<ref>{{Cite web|url=https://www.stat.washington.edu/~hoytak/blog/whypython.html|title=10 Reasons Python Rocks for Research (And a Few Reasons it Doesn't) – Hoyt Koepke|website=University of Washington Department of Statistics |access-date=3 February 2019|archive-date=31 May 2020|archive-url=https://web.archive.org/web/20200531211840/https://www.stat.washington.edu/~hoytak/blog/whypython.html|url-status=dead}}</ref><ref>{{Cite web|url=https://engineering.ucsb.edu/~shell/che210d/python.pdf|title=An introduction to Python for scientific computing|last=Shell|first=Scott|date=17 June 2014|access-date=3 February 2019|archive-date=4 February 2019|archive-url=https://web.archive.org/web/20190204014642/https://engineering.ucsb.edu/~shell/che210d/python.pdf|url-status=live}}</ref>
==Programming examples==
[["Hello, World!" program]]:
<syntaxhighlight lang="python">
print('Hello, world!')
</syntaxhighlight>
Program to calculate the [[factorial]] of a positive integer:
<syntaxhighlight lang="python" line="1">
n = int(input('Type a number, and its factorial will be printed: '))
if n < 0:
raise ValueError('You must enter a non-negative integer')
factorial = 1
for i in range(2, n + 1):
factorial *= i
print(factorial)
</syntaxhighlight><!--
Please don’t add more examples.
-->
==Libraries==
Python's large standard library<ref name="AutoNT-86" /> provides tools suited to many tasks and is commonly cited as one of its greatest strengths. For Internet-facing applications, many standard formats and protocols such as [[MIME]] and [[Hypertext Transfer Protocol|HTTP]] are supported. It includes modules for creating [[graphical user interface]]s, connecting to [[relational database]]s, [[pseudorandom number generator|generating pseudorandom numbers]], arithmetic with arbitrary-precision decimals,<ref name="AutoNT-88" /> manipulating [[regular expression]]s, and [[unit testing]].
Some parts of the standard library are covered by specifications—for example, the [[Web Server Gateway Interface]] (WSGI) implementation <code>wsgiref</code> follows PEP 333<ref name="AutoNT-89" />—but most are specified by their code, internal documentation, and [[test suite]]s. However, because most of the standard library is cross-platform Python code, only a few modules need altering or rewriting for variant implementations.
{{As of|2022|11|14|post=,}} the [[Python Package Index]] (PyPI), the official repository for third-party Python software, contains over 415,000<ref name="Modulecounts 2022">{{cite web |date=2022-11-14 |title=Modulecounts |url=http://www.modulecounts.com/ |url-status=live |archive-url=https://web.archive.org/web/20220626171519/http://www.modulecounts.com/ |archive-date=2022-06-26 |website=Modulecounts}}</ref> packages with a wide range of functionality, including:
{{columns-list|colwidth=30em|
* [[Automation]]
* [[Data analytics]]
* [[Database]]s
* [[Documentation]]
* [[Graphical user interface]]s
* [[Image processing]]
* [[Machine learning]]
* [[Mobile app]]s
* [[Multimedia]]
* [[Computer networking]]
* [[Scientific computing]]
* [[System administration]]
* [[Test framework]]s
* [[Text processing]]
* [[Web framework]]s
* [[Web scraping]]
}}
==Development environments==
{{See also|Comparison of integrated development environments#Python}}
Most Python implementations (including CPython) include a [[read–eval–print loop]] (REPL), permitting them to function as a [[command line interpreter]] for which users enter statements sequentially and receive results immediately.
Python also comes with an [[Integrated development environment|Integrated development environment (IDE)]] called [[IDLE]], which is more beginner-oriented.
Other shells, including [[IDLE]] and [[IPython]], add further abilities such as improved auto-completion, session state retention, and [[syntax highlighting]].
As well as standard desktop [[integrated development environment]]s including PyCharm, IntelliJ Idea, Visual Studio Code etc, there are [[web browser]]-based IDEs, including [[SageMath]], for developing science- and math-related programs; [[PythonAnywhere]], a browser-based IDE and hosting environment; and Canopy IDE, a commercial IDE emphasizing [[scientific computing]].<ref>{{cite web|last1=Enthought|first1=Canopy|title=Canopy|url=https://www.enthought.com/products/canopy/|website=www.enthought.com|access-date=20 August 2016|archive-date=15 July 2017|archive-url=https://web.archive.org/web/20170715151703/https://www.enthought.com/products/canopy/|url-status=dead}}</ref>
==Implementations==
{{See also|List of Python software#Python implementations}}
===Reference implementation===
[[CPython]] is the [[reference implementation]] of Python. It is written in C, meeting the [[C89 (C version)|C89]] standard (Python 3.11 uses [[C11 (C standard revision)|C11]]<ref>{{Cite web |title=PEP 7 – Style Guide for C Code {{!}} peps.python.org |url=https://peps.python.org/pep-0007/ |access-date=2022-04-28 |website=peps.python.org |archive-date=24 April 2022 |archive-url=https://web.archive.org/web/20220424202827/https://peps.python.org/pep-0007/ |url-status=live }}</ref>) with several select [[C99]] features. CPython includes its own C extensions, but third-party extensions are not limited to older C versions—e.g. they can be implemented with [[C11 (C standard revision)|C11]] or C++.<ref>{{Cite web|title=4. Building C and C++ Extensions – Python 3.9.2 documentation|url=https://docs.python.org/3/extending/building.html|access-date=2021-03-01|website=docs.python.org|archive-date=3 March 2021|archive-url=https://web.archive.org/web/20210303002519/https://docs.python.org/3/extending/building.html|url-status=live}}</ref><ref name="AutoNT-66" />) It [[Compiler|compiles]] Python programs into an intermediate [[bytecode]]<ref name="AutoNT-67" /> which is then executed by its [[virtual machine]].<ref name="AutoNT-68" /> CPython is distributed with a large standard library written in a mixture of C and native Python, and is available for many platforms, including Windows (<!--"Windows Vista support dropped in Python 3.7"-->starting with Python 3.9, the Python installer deliberately fails to install on [[Windows 7]] and 8;<ref>{{Cite web|title=Changelog – Python 3.9.0 documentation|url=https://docs.python.org/release/3.9.0/whatsnew/changelog.html#changelog|access-date=2021-02-08|website=docs.python.org|archive-date=7 February 2021|archive-url=https://web.archive.org/web/20210207001142/https://docs.python.org/release/3.9.0/whatsnew/changelog.html#changelog|url-status=live}}</ref><ref>{{Cite web|title=Download Python|url=https://www.python.org/downloads/release/python-391|access-date=2020-12-13|website=Python.org|language=en|archive-date=8 December 2020|archive-url=https://web.archive.org/web/20201208045225/https://www.python.org/downloads/release/python-391/|url-status=live}}</ref> [[Windows XP]] was supported until Python 3.5<!--"Windows XP support dropped in Python 3.5"-->) and most modern [[Unix-like]] systems, including macOS (and [[Apple M1]] Macs, since Python 3.9.1, with experimental installer) and unofficial support for e.g. [[OpenVMS|VMS]].<!--"Put online a new version of Python 3.10.0a (IA64only)"--><ref>{{Cite web|title=history [vmspython]|url=https://www.vmspython.org/doku.php?id=history|access-date=2020-12-04|website=www.vmspython.org|archive-date=2 December 2020|archive-url=https://web.archive.org/web/20201202194743/https://www.vmspython.org/doku.php?id=history|url-status=live}}</ref> Platform portability was one of its earliest priorities.<ref name="AutoNT-69" /> (During Python 1 and 2 development, even [[OS/2]] and [[Solaris (operating system)|Solaris]] were supported,<!-- Also python-3.2.2 at http://unixpackages.com/packages/package-list --><ref>{{Cite web|title=Download Python for Other Platforms|url=https://www.python.org/download/other/|access-date=2020-12-04|website=Python.org|language=en|archive-date=27 November 2020|archive-url=https://web.archive.org/web/20201127015815/https://www.python.org/download/other/|url-status=live}}</ref> but support has since been dropped for many platforms.)<!--
Include more, here or in the infobox? I find e.g.:
best-effort support:
Android API 24
and also:
Starting with CPython 3.7.0, *nix platforms are expected to provide at least one of C.UTF-8 (full locale), C.utf8 (full locale) or UTF-8 (LC_CTYPE-only locale) as an alternative to the legacy C locale.
-->
===Other implementations===
* [[PyPy]] is a fast, compliant interpreter of Python 2.7 and 3.8.<ref name="AutoNT-70" /><ref>{{Cite web|last=Team|first=The PyPy|date=2019-12-28|title=Download and Install|url=https://www.pypy.org/download.html|access-date=2022-01-08|website=PyPy|language=en|archive-date=8 January 2022|archive-url=https://web.archive.org/web/20220108212951/https://www.pypy.org/download.html|url-status=live}}</ref> Its [[Just-in-time compilation|just-in-time compiler]] often brings a significant speed improvement over CPython but some libraries written in C cannot be used with it.<ref name="AutoNT-71" />
* [[Stackless Python]] is a significant fork of CPython that implements [[microthread]]s; it does not use the [[call stack]] in the same way, thus allowing massively concurrent programs. PyPy also has a stackless version.<ref name="AutoNT-73" />
* [[MicroPython]] and [[CircuitPython]] are Python 3 variants optimized for [[microcontroller]]s, including [[Lego Mindstorms EV3]].<ref>{{Cite web|url=https://education.lego.com/en-us/support/mindstorms-ev3/python-for-ev3|title=Python-for-EV3|website=LEGO Education|language=en|access-date=17 April 2019|archive-date=7 June 2020|archive-url=https://web.archive.org/web/20200607234814/https://education.lego.com/en-us/support/mindstorms-ev3/python-for-ev3|url-status=live}}</ref>
* Pyston is a variant of the Python runtime that uses just-in-time compilation to speed up the execution of Python programs.<ref>{{cite news|url=https://www.infoworld.com/article/3587591/pyston-returns-from-the-dead-to-speed-python.html|title=Pyston returns from the dead to speed Python|last=Yegulalp|first=Serdar|date=29 October 2020|website=[[InfoWorld]]|access-date=26 January 2021|archive-date=27 January 2021|archive-url=https://web.archive.org/web/20210127113233/https://www.infoworld.com/article/3587591/pyston-returns-from-the-dead-to-speed-python.html|url-status=live}}</ref>
* Cinder is a performance-oriented fork of CPython 3.8 that contains a number of optimizations, including bytecode inline caching, eager evaluation of coroutines, a method-at-a-time [[Just-in-time compilation|JIT]], and an experimental bytecode compiler.<ref>{{Cite web|url=https://github.com/facebookincubator/cinder|title=cinder: Instagram's performance-oriented fork of CPython.|website=[[GitHub]]|access-date=4 May 2021|language=en|archive-date=4 May 2021|archive-url=https://web.archive.org/web/20210504112500/https://github.com/facebookincubator/cinder|url-status=live}}</ref>
* [https://sneklang.org/ Snek]<!-- (previously named Newt) --><ref>{{Cite web |last=Aroca |first=Rafael |date=2021-08-07 |title=Snek Lang: feels like Python on Arduinos |url=https://rafaelaroca.wordpress.com/2021/08/07/snek-lang-feels-like-python-on-arduinos/ |access-date=2024-01-04 |website=Yet Another Technology Blog |language=en}}</ref><ref>{{Cite web |last=Aufranc (CNXSoft) |first=Jean-Luc |date=2020-01-16 |title=Snekboard Controls LEGO Power Functions with CircuitPython or Snek Programming Languages (Crowdfunding) - CNX Software |url=https://www.cnx-software.com/2020/01/16/snekboard-controls-lego-power-functions-with-circuitpython-or-snek-programming-languages/ |access-date=2024-01-04 |website=CNX Software - Embedded Systems News |language=en-US}}</ref><ref>{{Cite web |last=Kennedy (@mkennedy) |first=Michael |title=Ready to find out if you're git famous? |url=https://pythonbytes.fm/episodes/show/187/ready-to-find-out-if-youre-git-famous |access-date=2024-01-04 |website=pythonbytes.fm |language=en-US}}</ref><!-- https://keithp.com/blogs/newt-lola/ https://bipes.net.br/snek-web-uploader/ --> Embedded Computing Language (supporting e.g. 8-bit [[AVR microcontrollers]] such as [[ATmega|ATmega 328P]]-based Arduino, and larger ones that are [[MicroPython]] can also support) "is Python-inspired, but it is not Python. It is possible to write Snek programs that run under a full Python system, but most Python programs will not run under Snek." It's an imperative language not including [[Object-oriented programming|OOP]]/classes unlike Python, and simplifying to one number type (like [[JavaScript]], except using smaller) 32-bit [[single-precision]] "Integer values of less than 24 bits can be represented exactly in these floating point values".<ref>{{Cite web |last=Packard |first=Keith |date=2022-12-20 |title=The Snek Programming Language: A Python-inspired Embedded Computing Language |url=https://sneklang.org/doc/snek.pdf}}</ref> <!-- "Snek is a tiny embeddable language targeting processors with only a few kB of flash and ram. Think of something that would have been running BASIC years ago and you'll have the idea. These processors are too small to run MicroPython." "Snekboard is a custom embedded computer designed to run Snek or CircuitPython." -->
===Unsupported implementations===
Other just-in-time Python compilers have been developed, but are now unsupported:
* Google began a project named [[Unladen Swallow]] in 2009, with the aim of speeding up the Python interpreter fivefold by using the [[LLVM]], and of improving its [[Multithreading (computer architecture)|multithreading]] ability to scale to thousands of cores,<ref name="AutoNT-74" /> while ordinary implementations suffer from the [[global interpreter lock]].
* [[Psyco]] is a discontinued [[Just-in-time compilation|just-in-time]] [[run-time algorithm specialization|specializing]] compiler that integrates with CPython and transforms bytecode to machine code at runtime. The emitted code is specialized for certain [[data type]]s and is faster than the standard Python code. Psyco does not support Python 2.7 or later.
* [[PyS60]] was a Python 2 interpreter for [[Series 60]] mobile phones released by [[Nokia]] in 2005. It implemented many of the modules from the standard library and some additional modules for integrating with the [[Symbian]] operating system. The Nokia [[N900]] also supports Python with [[GTK]] widget libraries, enabling programs to be written and run on the target device.<ref>{{cite web|title=Python on the Nokia N900|url=http://www.stochasticgeometry.ie/2010/04/29/python-on-the-nokia-n900/|website=Stochastic Geometry|date=29 April 2010|access-date=9 July 2015|archive-date=20 June 2019|archive-url=https://web.archive.org/web/20190620000053/http://www.stochasticgeometry.ie/2010/04/29/python-on-the-nokia-n900/|url-status=live}}</ref>
===Cross-compilers to other languages===
There are several compilers/[[transpiler]]s to high-level object languages, with either unrestricted Python, a restricted subset of Python, or a language similar to Python as the source language:
* Brython,<ref>{{Cite web|title=Brython|url=https://brython.info/|access-date=2021-01-21|website=brython.info|archive-date=3 August 2018|archive-url=https://web.archive.org/web/20180803065954/http://brython.info/|url-status=live}}</ref> Transcrypt<ref>{{cite web|title=Transcrypt – Python in the browser|url=https://www.transcrypt.org|access-date=22 December 2020|website=transcrypt.org|language=en|archive-date=19 August 2018|archive-url=https://web.archive.org/web/20180819133303/http://www.transcrypt.org/|url-status=live}}</ref><ref>{{Cite web|url=https://www.infoq.com/articles/transcrypt-python-javascript-compiler/|title=Transcrypt: Anatomy of a Python to JavaScript Compiler|website=InfoQ|access-date=20 January 2021|archive-date=5 December 2020|archive-url=https://web.archive.org/web/20201205193339/https://www.infoq.com/articles/transcrypt-python-javascript-compiler/|url-status=live}}</ref> and [[Pyjs]] (latest release in 2012) compile Python to [[JavaScript]].
* [https://github.com/exaloop/codon Codon] compiles a subset of statically typed Python<ref>{{Cite web |title=Codon: Differences with Python |url=https://docs.exaloop.io/codon/general/differences |url-status=live |archive-url=https://web.archive.org/web/20230525002540/https://docs.exaloop.io/codon/general/differences |archive-date=2023-05-25 |access-date=2023-08-28}}</ref> to machine code (via [[LLVM]]) and supports native multithreading.<ref>{{Cite web |last=Lawson |first=Loraine |date=2023-03-14 |title=MIT-Created Compiler Speeds up Python Code |url=https://thenewstack.io/mit-created-compiler-speeds-up-python-code/ |url-status=live |archive-url=https://web.archive.org/web/20230406054200/https://thenewstack.io/mit-created-compiler-speeds-up-python-code/ |archive-date=2023-04-06 |access-date=2023-08-28 |website=The New Stack |language=en-US}}</ref>
* [[Cython]] compiles (a superset of) Python <!-- actually 2.7 by default, but Python 3 by override --> to C. The resulting code is also usable with Python via direct C-level API calls into the Python interpreter.
* PyJL compiles/transpiles a subset of Python to "human-readable, maintainable, and high-performance Julia source code".<ref name=PyJL>{{Cite web |title=Transpiling Python to Julia using PyJL |url=https://web.ist.utl.pt/antonio.menezes.leitao/ADA/documents/publications_docs/2022_TranspilingPythonToJuliaUsingPyJL.pdf|quote=After manually modifying one line of code by specifying the necessary type information, we obtained a speedup of 52.6×, making the translated Julia code 19.5× faster than the original Python code.}}</ref> Despite claiming high performance, no tool can claim to do that for ''arbitrary'' Python code; i.e. it's known not possible to compile to a faster language or machine code. Unless semantics of Python are changed, but in many cases speedup is possible with few or no changes in the Python code. The faster Julia source code can then be used from Python, or compiled to machine code, and based that way.
* [[Nuitka]] compiles Python into C.<ref>{{cite web|title=Nuitka Home {{!}} Nuitka Home|url=http://nuitka.net/|access-date=18 August 2017|website=nuitka.net|language=en|archive-date=30 May 2020|archive-url=https://web.archive.org/web/20200530211233/https://nuitka.net/|url-status=live}}</ref>
* [[Numba]] uses LLVM to compile a subset of Python to machine code.
* Pythran compiles a subset of Python 3 to C++ ([[C++11]]).<ref name="Guelton Brunet Amini Merlini 2015 p=014001">{{cite journal |last1=Guelton |first1=Serge |last2=Brunet |first2=Pierrick |last3=Amini |first3=Mehdi |last4=Merlini |first4=Adrien |last5=Corbillon |first5=Xavier |last6=Raynaud |first6=Alan |title=Pythran: enabling static optimization of scientific Python programs |journal=Computational Science & Discovery |publisher=IOP Publishing |volume=8 |issue=1 |date=16 March 2015 |issn=1749-4699 |doi=10.1088/1749-4680/8/1/014001|doi-access=free |page=014001| bibcode=2015CS&D....8a4001G}}</ref>
* [[RPython]] can be compiled to C, and is used to build the PyPy interpreter of Python.
* The Python → 11l → C++ transpiler<ref>{{Cite web |url=https://11l-lang.org/transpiler |title=The Python → 11l → C++ transpiler |access-date=17 July 2022 |archive-date=24 September 2022 |archive-url=https://web.archive.org/web/20220924233728/https://11l-lang.org/transpiler/ |url-status=live }}</ref> compiles a subset of Python 3 to C++ ([[C++17]]).
Specialized:
* [[MyHDL]] is a Python-based [[hardware description language]] (HDL), that converts MyHDL code to [[Verilog]] or [[VHDL]] code.
Older projects (or not to be used with Python 3.x and latest syntax):
* Google's Grumpy (latest release in 2017) [[transpile]]s Python 2 to [[Go (programming language)|Go]].<ref>{{Cite web|url=https://github.com/google/grumpy|title=google/grumpy|date=10 April 2020|via=GitHub|access-date=25 March 2020|archive-date=15 April 2020|archive-url=https://web.archive.org/web/20200415054919/https://github.com/google/grumpy|url-status=live}}</ref><ref>{{Cite web|url=https://opensource.google/projects/|title=Projects|website=opensource.google|access-date=25 March 2020|archive-date=24 April 2020|archive-url=https://web.archive.org/web/20200424191248/https://opensource.google/projects/|url-status=live}}</ref><ref>{{Cite web|url=https://www.theregister.com/2017/01/05/googles_grumpy_makes_python_go/|title=Google's Grumpy code makes Python Go|first=Thomas Claburn in San|last=Francisco|website=www.theregister.com|access-date=20 January 2021|archive-date=7 March 2021|archive-url=https://web.archive.org/web/20210307165521/https://www.theregister.com/2017/01/05/googles_grumpy_makes_python_go/|url-status=live}}</ref>
* [[IronPython]] <!-- (abandoned by Microsoft) --> allows running Python 2.7 programs (and an [[Software release life cycle#Alpha|alpha]], released in 2021, is also available for "Python 3.4, although features and behaviors from later versions may be included"<ref>{{Cite web |url=https://github.com/IronLanguages/ironpython3 |title=GitHub – IronLanguages/ironpython3: Implementation of Python 3.x for .NET Framework that is built on top of the Dynamic Language Runtime<!-- Bot generated title --> |website=[[GitHub]] |archive-date=28 September 2021 |archive-url=https://web.archive.org/web/20210928101250/https://github.com/IronLanguages/ironpython3 |url-status=live}}</ref>) on the .NET [[Common Language Runtime]].<ref>{{Cite web|title=IronPython.net /|url=https://ironpython.net/|website=ironpython.net|archive-date=17 April 2021|archive-url=https://web.archive.org/web/20210417064418/https://ironpython.net/|url-status=live}}</ref>
* [[Jython]] compiles Python 2.7 to Java bytecode, allowing the use of the Java libraries from a Python program.<ref>{{Cite web|title=Jython FAQ|url=https://www.jython.org/jython-old-sites/archive/22/userfaq.html|access-date=2021-04-22|website=www.jython.org|archive-date=22 April 2021|archive-url=https://web.archive.org/web/20210422055726/https://www.jython.org/jython-old-sites/archive/22/userfaq.html|url-status=live}}</ref>
* [[Pyrex (programming language)|Pyrex]] (latest release in 2010) and [[Shed Skin]] (latest release in 2013) compile to C and C++ respectively.
===Performance===
Performance comparison of various Python implementations on a non-numerical (combinatorial) workload was presented at EuroSciPy '13.<ref>{{cite conference |title=Performance of Python runtimes on a non-numeric scientific code |last=Murri |first=Riccardo |conference=European Conference on Python in Science (EuroSciPy) |year=2013 |arxiv=1404.6388|bibcode=2014arXiv1404.6388M}}</ref> Python's performance compared to other programming languages is also benchmarked by [[The Computer Language Benchmarks Game]].<ref>{{cite web|title=The Computer Language Benchmarks Game|url=https://benchmarksgame-team.pages.debian.net/benchmarksgame/fastest/python.html|access-date=30 April 2020|archive-date=14 June 2020|archive-url=https://web.archive.org/web/20200614210246/https://benchmarksgame-team.pages.debian.net/benchmarksgame/fastest/python.html|url-status=live}}</ref>
==Development==
Python's development is conducted largely through the ''Python Enhancement Proposal'' (PEP) process, the primary mechanism for proposing major new features, collecting community input on issues, and documenting Python design decisions.<ref name="PepCite000" /> Python coding style is covered in PEP 8.<ref>{{cite web|url=https://www.python.org/dev/peps/pep-0008/|title=PEP 8 – Style Guide for Python Code|website=Python.org|access-date=26 March 2019|archive-date=17 April 2019|archive-url=https://web.archive.org/web/20190417223549/https://www.python.org/dev/peps/pep-0008/|url-status=live}}</ref> Outstanding PEPs are reviewed and commented on by the Python community and the steering council.<ref name="PepCite000" />
Enhancement of the language corresponds with the development of the CPython reference implementation. The mailing list python-dev is the primary forum for the language's development. Specific issues were originally discussed in the [[Roundup (issue tracker)|Roundup]] [[bug tracker]] hosted at by the foundation.<ref name="AutoNT-21" /> In 2022, all issues and discussions were migrated to [[GitHub]].<ref>{{cite web |url=https://lwn.net/Articles/885854/ |title=Moving Python's bugs to GitHub [LWN.net] |access-date=2 October 2022 |archive-date=2 October 2022 |archive-url=https://web.archive.org/web/20221002183818/https://lwn.net/Articles/885854/ |url-status=live }}</ref> Development originally took place on a [[Self-hosting (web services)|self-hosted]] source-code repository running [[Mercurial]], until Python moved to [[GitHub]] in January 2017.<ref name=py_dev_guide>{{Cite web|url=https://devguide.python.org/|title=Python Developer's Guide – Python Developer's Guide|website=devguide.python.org|access-date=17 December 2019|archive-date=9 November 2020|archive-url=https://web.archive.org/web/20201109032501/https://devguide.python.org/|url-status=live}}</ref>
CPython's public releases come in three types, distinguished by which part of the version number is incremented:
* Backward-incompatible versions, where code is expected to break and needs to be manually [[ported]]. The first part of the version number is incremented. These releases happen infrequently—version 3.0 was released 8 years after 2.0. According to Guido van Rossum, a version 4.0 is very unlikely to ever happen.<ref>{{Cite web |last=Hughes |first=Owen |date=2021-05-24 |title=Programming languages: Why Python 4.0 might never arrive, according to its creator |url=https://www.techrepublic.com/article/programming-languages-why-python-4-0-will-probably-never-arrive-according-to-its-creator/ |access-date=2022-05-16 |website=TechRepublic |language=en-US |archive-date=14 July 2022 |archive-url=https://web.archive.org/web/20220714201302/https://www.techrepublic.com/article/programming-languages-why-python-4-0-will-probably-never-arrive-according-to-its-creator/ |url-status=live }}</ref>
* Major or "feature" releases are largely compatible with the previous version but introduce new features. The second part of the version number is incremented. Starting with Python 3.9, these releases are expected to happen annually.<ref>{{Cite web|url=https://www.python.org/dev/peps/pep-0602/|title=PEP 602 – Annual Release Cycle for Python|website=Python.org|language=en|access-date=6 November 2019|archive-date=14 June 2020|archive-url=https://web.archive.org/web/20200614202755/https://www.python.org/dev/peps/pep-0602/|url-status=live}}</ref><ref>{{Cite web|url=https://lwn.net/Articles/802777/|title=Changing the Python release cadence [LWN.net]|website=lwn.net|access-date=6 November 2019|archive-date=6 November 2019|archive-url=https://web.archive.org/web/20191106170153/https://lwn.net/Articles/802777/|url-status=live}}</ref> Each major version is supported by bug fixes for several years after its release.<ref name="release-schedule" />
* Bugfix releases,<ref name="AutoNT-22" /> which introduce no new features, occur about every 3 months and are made when a sufficient number of bugs have been fixed upstream since the last release. Security vulnerabilities are also patched in these releases. The third and final part of the version number is incremented.<ref name="AutoNT-22" />
Many [[beta release|alpha, beta, and release-candidates]] are also released as previews and for testing before final releases. Although there is a rough schedule for each release, they are often delayed if the code is not ready. Python's development team monitors the state of the code by running the large [[unit test]] suite during development.<ref name="AutoNT-23" />
The major [[academic conference]] on Python is [[PyCon]]. There are also special Python mentoring programs, such as [[PyLadies]].
Python 3.12 removed <code>wstr</code> meaning Python extensions<ref>{{Cite web|title=1. Extending Python with C or C++ – Python 3.9.1 documentation|url=https://docs.python.org/3/extending/extending.html|access-date=2021-02-14|website=docs.python.org|archive-date=23 June 2020|archive-url=https://web.archive.org/web/20200623232830/https://docs.python.org/3/extending/extending.html|url-status=live}}</ref> need to be modified,<ref>{{Cite web|title=PEP 623 – Remove wstr from Unicode|url=https://www.python.org/dev/peps/pep-0623/|access-date=2021-02-14|website=Python.org|language=en|archive-date=5 March 2021|archive-url=https://web.archive.org/web/20210305153214/https://www.python.org/dev/peps/pep-0623/|url-status=live}}</ref> and 3.10 added [[pattern matching]] to the language.<ref>{{Cite web|title=PEP 634 – Structural Pattern Matching: Specification|url=https://www.python.org/dev/peps/pep-0634/|access-date=2021-02-14|website=Python.org|language=en|archive-date=6 May 2021|archive-url=https://web.archive.org/web/20210506005315/https://www.python.org/dev/peps/pep-0634/|url-status=live}}</ref>
Python 3.12 dropped some outdated modules, and more will be dropped in the future, deprecated as of 3.13; already deprecated array 'u' format code will emit <code>DeprecationWarning</code> since 3.13 and will be removed in Python 3.16. The 'w' format code should be used instead. Part of ctypes is also deprecated and <code>http.server.CGIHTTPRequestHandler</code> will emit a DeprecationWarning, and will be removed in 3.15. Using that code already has a high potential for both security and functionality bugs. Parts of the typing module are deprecated, e.g. creating a <code>typing.NamedTuple</code> class using keyword arguments to denote the fields and such (and more) will be disallowed in Python 3.15.
==API documentation generators==
Tools that can generate documentation for Python API include [[pydoc]] (available as part of the standard library), [[Sphinx (documentation generator)|Sphinx]], [[Pdoc]] and its forks, [[Doxygen]] and [[Graphviz]], among others.<ref>{{Cite web |title=Documentation Tools |url=https://wiki.python.org/moin/DocumentationTools |access-date=2021-03-22 |website=Python.org |language=en |archive-date=11 November 2020 |archive-url=https://web.archive.org/web/20201111173635/https://wiki.python.org/moin/DocumentationTools |url-status=live}}</ref>
==Naming==
Python's name is derived from the British comedy group [[Monty Python]], whom Python creator Guido van Rossum enjoyed while developing the language. Monty Python references appear frequently in Python code and culture;<ref name="tutorial-chapter1" /> for example, the [[metasyntactic variable]]s often used in Python literature are [[Spam (Monty Python)|''spam'' and ''eggs'']] instead of the traditional [[foobar|''foo'' and ''bar'']].<ref name="tutorial-chapter1" /><ref name="AutoNT-26" /> The official Python documentation also contains various references to Monty Python routines.<ref>{{cite book |last1=Lutz |first1=Mark |title=Learning Python: Powerful Object-Oriented Programming |year=2009 |publisher=O'Reilly Media, Inc. |isbn=9781449379322 |page=17 |url=https://books.google.com/books?id=1HxWGezDZcgC&pg=PA17 |language=en |access-date=9 May 2017 |archive-date=17 July 2017 |archive-url=https://web.archive.org/web/20170717044012/https://books.google.com/books?id=1HxWGezDZcgC&pg=PA17 |url-status=live}}</ref><ref>{{cite book |last1=Fehily |first1=Chris |title=Python |year=2002 |publisher=Peachpit Press |isbn=9780201748840 |page=xv |url=https://books.google.com/books?id=carqdIdfVlYC&pg=PR15 |language=en |access-date=9 May 2017 |archive-date=17 July 2017 |archive-url=https://web.archive.org/web/20170717044040/https://books.google.com/books?id=carqdIdfVlYC&pg=PR15 |url-status=live}}</ref> Users of Python are sometimes referred to as "Pythonistas".<ref name="introducing_python">{{Cite book| publisher = Sebastopol, CA : O'Reilly Media| isbn = 978-1-4493-5936-2| last = Lubanovic| first = Bill| title = Introducing Python| access-date = 2023-07-31| date = 2014| url = http://archive.org/details/introducingpytho0000luba| page=305}}</ref>
The prefix ''Py-'' is used to show that something is related to Python. Examples of the use of this prefix in names of Python applications or libraries include [[Pygame]], a [[language binding|binding]] of [[Simple DirectMedia Layer|SDL]] to Python (commonly used to create games); [[PyQt]] and [[PyGTK]], which bind [[Qt (software)|Qt]] and GTK to Python respectively; and [[PyPy]], a Python implementation originally written in Python.
==Popularity==
Since 2003, Python has consistently ranked in the top ten most popular programming languages in the [[TIOBE Programming Community Index]] where {{as of|2022|12|lc=y}} it was the most popular language (ahead of C, C++, and [[Java (programming language)|Java]]).<ref name=tiobecurrent/> It was selected Programming Language of the Year (for "the highest rise in ratings in a year") in 2007, 2010, 2018, and 2020 (the only language to have done so four times {{as of|2020|lc=true}}<ref>{{Cite web|last=Blake|first=Troy|date=2021-01-18|title=TIOBE Index for January 2021|url=https://seniordba.wordpress.com/2021/01/18/tiobe-index-for-january-2021/|access-date=2021-02-26|website=Technology News and Information by SeniorDBA|language=en|archive-date=21 March 2021|archive-url=https://web.archive.org/web/20210321143253/https://seniordba.wordpress.com/2021/01/18/tiobe-index-for-january-2021/|url-status=live}}</ref>).
An empirical study found that scripting languages, such as Python, are more productive than conventional languages, such as C and Java, for programming problems involving string manipulation and search in a dictionary, and determined that memory consumption was often "better than Java and not much worse than C or C++".<ref name="AutoNT-28" />
Large organizations that use Python include [[Wikipedia]], [[Google]],<ref name="quotes-about-python" /> [[Yahoo!]],<ref name="AutoNT-29" /> [[CERN]],<ref name="AutoNT-30" /> [[NASA]],<ref name="AutoNT-31" /> [[Facebook]],<ref>{{Cite web|url=https://developers.facebook.com/blog/post/301|title=Tornado: Facebook's Real-Time Web Framework for Python – Facebook for Developers|website=Facebook for Developers|language=en-US|access-date=19 June 2018|archive-date=19 February 2019|archive-url=https://web.archive.org/web/20190219031313/https://developers.facebook.com/blog/post/301|url-status=live}}</ref> [[Amazon (company)|Amazon]], [[Instagram]],<ref>{{cite web |url=https://instagram-engineering.com/what-powers-instagram-hundreds-of-instances-dozens-of-technologies-adf2e22da2ad |title=What Powers Instagram: Hundreds of Instances, Dozens of Technologies |date=11 December 2016 |publisher=Instagram Engineering |access-date=27 May 2019 |archive-date=15 June 2020 |archive-url=https://web.archive.org/web/20200615183410/https://instagram-engineering.com/what-powers-instagram-hundreds-of-instances-dozens-of-technologies-adf2e22da2ad |url-status=live}}</ref> [[Spotify]],<ref>{{Cite web|url=https://labs.spotify.com/2013/03/20/how-we-use-python-at-spotify/|title=How we use Python at Spotify|website=Spotify Labs|language=en-US|access-date=25 July 2018|date=20 March 2013|archive-date=10 June 2020|archive-url=https://web.archive.org/web/20200610005143/https://labs.spotify.com/2013/03/20/how-we-use-python-at-spotify/|url-status=live}}</ref> and some smaller entities like [[Industrial Light & Magic|ILM]]<ref name="AutoNT-32" /> and [[ITA Software|ITA]].<ref name="AutoNT-33" /> The social news networking site [[Reddit]] was written mostly in Python.<ref>{{Citation|title=GitHub – reddit-archive/reddit: historical code from reddit.com.|url=https://github.com/reddit-archive/reddit|publisher=The Reddit Archives|access-date=20 March 2019|archive-date=1 June 2020|archive-url=https://web.archive.org/web/20200601104939/https://github.com/reddit-archive/reddit|url-status=live}}</ref>
==Uses==
{{Main|List of Python software}}
[[File:Python Powered.png|thumb|Python Powered]]
Python can serve as a [[scripting language]] for [[web application]]s, e.g. via {{Not a typo|[[mod_wsgi]]}} for the [[Apache webserver]].<ref name="AutoNT-35" /> With [[Web Server Gateway Interface]], a standard API has evolved to facilitate these applications. [[Web framework]]s like [[Django (web framework)|Django]], [[Pylons (web framework)|Pylons]], [[Pyramid (web framework)|Pyramid]], [[TurboGears]], [[web2py]], [[Tornado (web server)|Tornado]], [[Flask (web framework)|Flask]], Bottle, and [[Zope]] support developers in the design and maintenance of complex applications. Pyjs and [[IronPython]] can be used to develop the client-side of Ajax-based applications. [[SQLAlchemy]] can be used as a [[Data mapper pattern|data mapper]] to a relational database. [[Twisted (software)|Twisted]] is a framework to program communications between computers, and is used (for example) by [[Dropbox (service)|Dropbox]].
Libraries such as [[NumPy]], [[SciPy]] and [[Matplotlib]] allow the effective use of Python in scientific computing,<ref name="cise">{{cite journal |last=Oliphant |first=Travis |title=Python for Scientific Computing |journal=Computing in Science and Engineering |volume=9 |issue=3 |pages=10–20 |year=2007 |url=https://www.h2desk.com/blog/python-scientific-computing/ |doi=10.1109/MCSE.2007.58 |citeseerx=10.1.1.474.6460 |bibcode=2007CSE.....9c..10O |s2cid=206457124 |access-date=10 April 2015 |archive-date=15 June 2020 |archive-url=https://web.archive.org/web/20200615193226/https://www.h2desk.com/blog/python-scientific-computing/ |url-status=live}}</ref><ref name="millman">{{cite journal |first1=K. Jarrod |last1=Millman |first2=Michael |last2=Aivazis |title=Python for Scientists and Engineers |journal=Computing in Science and Engineering |volume=13 |number=2 |pages=9–12 |year=2011 |url=http://www.computer.org/csdl/mags/cs/2011/02/mcs2011020009.html |doi=10.1109/MCSE.2011.36 |bibcode=2011CSE....13b...9M |access-date=7 July 2014 |archive-date=19 February 2019 |archive-url=https://web.archive.org/web/20190219031439/https://www.computer.org/csdl/mags/cs/2011/02/mcs2011020009.html |url-status=live}}</ref> with specialized libraries such as [[Biopython]] and [[Astropy]] providing ___domain-specific functionality. [[SageMath]] is a [[computer algebra system]] with a [[notebook interface]] programmable in Python: its library covers many aspects of [[mathematics]], including [[algebra]], [[combinatorics]], [[numerical mathematics]], [[number theory]], and [[calculus]].<ref name="ICSE" >{{Citation|title=Science education with SageMath|url=http://visual.icse.us.edu.pl/methodology/why_Sage.html|publisher=Innovative Computing in Science Education|access-date=22 April 2019|archive-date=15 June 2020|archive-url=https://web.archive.org/web/20200615180428/http://visual.icse.us.edu.pl/methodology/why_Sage.html|url-status=dead}}</ref> [[OpenCV]] has Python bindings with a rich set of features for [[computer vision]] and [[Digital image processing|image processing]].<ref>{{Cite web|title=OpenCV: OpenCV-Python Tutorials|url=https://docs.opencv.org/3.4.9/d6/d00/tutorial_py_root.html|access-date=2020-09-14|website=docs.opencv.org|archive-date=23 September 2020|archive-url=https://web.archive.org/web/20200923063145/https://docs.opencv.org/3.4.9/d6/d00/tutorial_py_root.html|url-status=live}}</ref>
Python is commonly used in [[artificial intelligence]] projects and machine learning projects with the help of libraries like [[TensorFlow]], [[Keras]], [[PyTorch|Pytorch]], [[scikit-learn]] and the Logic language [[ProbLog]].<ref name=whitepaper2015>{{cite web |last1=Dean |first1=Jeff |last2=Monga |first2=Rajat |first3=Sanjay |last3=Ghemawat |display-authors=2 |author-link1=Jeff Dean (computer scientist) |title=TensorFlow: Large-scale machine learning on heterogeneous systems |url=http://download.tensorflow.org/paper/whitepaper2015.pdf |website=TensorFlow.org |publisher=Google Research |access-date=10 November 2015 |date=9 November 2015 |archive-date=20 November 2015 |archive-url=https://web.archive.org/web/20151120004649/http://download.tensorflow.org/paper/whitepaper2015.pdf |url-status=live}}</ref><ref>{{cite web |last1=Piatetsky |first1=Gregory |title=Python eats away at R: Top Software for Analytics, Data Science, Machine Learning in 2018: Trends and Analysis |url=https://www.kdnuggets.com/2018/05/poll-tools-analytics-data-science-machine-learning-results.html/2 |website=KDnuggets |access-date=30 May 2018 |archive-date=15 November 2019 |archive-url=https://web.archive.org/web/20191115234216/https://www.kdnuggets.com/2018/05/poll-tools-analytics-data-science-machine-learning-results.html/2 |url-status=live}}</ref><ref>{{cite web|url=https://scikit-learn.org/stable/testimonials/testimonials.html|title=Who is using scikit-learn? – scikit-learn 0.20.1 documentation|website=scikit-learn.org|access-date=30 November 2018|archive-date=6 May 2020|archive-url=https://web.archive.org/web/20200506210716/https://scikit-learn.org/stable/testimonials/testimonials.html|url-status=live}}</ref><ref>{{cite web |author-link1=Norman Jouppi |last1=Jouppi |first1=Norm |title=Google supercharges machine learning tasks with TPU custom chip |url=https://cloudplatform.googleblog.com/2016/05/Google-supercharges-machine-learning-tasks-with-custom-chip.html |website=Google Cloud Platform Blog |access-date=19 May 2016 |archive-date=18 May 2016 |archive-url=https://web.archive.org/web/20160518201516/https://cloudplatform.googleblog.com/2016/05/Google-supercharges-machine-learning-tasks-with-custom-chip.html |url-status=live}}</ref><ref name="ProbLogConcepts">{{cite journal
|last1 = De Raedt|first1 = Luc|last2 = Kimmig|first2 = Angelika|title = Probabilistic (logic) programming concepts|journal = Machine Learning|date = 2015|volume = 100|number = 1|pages = 5–47| doi=10.1007/s10994-015-5494-z | s2cid=3166992 |doi-access = free}}</ref> As a scripting language with a [[modular programming|modular architecture]], simple syntax, and rich text processing tools, Python is often used for [[natural language processing]].<ref name="AutoNT-47" />
The combination of Python and [[Prolog]] has proved to be particularly useful for AI applications, with Prolog providing knowledge representation and reasoning capablities. The Janus system, in particular, exploits the similarites between these two languages,
in part because of their use of dynamic typing, and the simple recursive nature of their
data structures. Typical applications of this combination include natural language processing, visual query
answering, geospatial reasoning, and handling of semantic web data.<ref>Andersen, C. and Swift, T., 2023. The Janus System: a bridge to new prolog applications. In Prolog: The Next 50 Years (pp. 93-104). Cham: Springer Nature Switzerland.</ref>
The Natlog system, implemented in Python, uses [[Definite clause grammar|Definite Clause Grammars]] (DCGs) as prompt generators for text-to-text generators like GPT3 and text-to-image generators like DALL-E or Stable Diffusion.<ref>Tarau, P., 2023. Reflections on automation, learnability and expressiveness in logic-based programming languages. In Prolog: The Next 50 Years (pp. 359-371). Cham: Springer Nature Switzerland.</ref>
Python can also be used for [[graphical user interface]] (GUI) by using libraries like [[Tkinter]].<ref>{{cite web | url=https://docs.python.org/3/library/tkinter.html | title=Tkinter — Python interface to TCL/Tk | access-date=9 June 2023 | archive-date=18 October 2012 | archive-url=https://web.archive.org/web/20121018043136/http://docs.python.org/library/tkinter.html | url-status=live }}</ref><ref>{{cite web | url=https://www.geeksforgeeks.org/python-tkinter-tutorial/ | title=Python Tkinter Tutorial | date=3 June 2020 | access-date=9 June 2023 | archive-date=9 June 2023 | archive-url=https://web.archive.org/web/20230609031631/https://www.geeksforgeeks.org/python-tkinter-tutorial/ | url-status=live }}</ref>
Python can also be used to create games, with libraries such as [[Pygame]], which can make 2D games.
Python has been successfully embedded in many software products as a scripting language, including in [[finite element method]] software such as [[Abaqus]], 3D parametric modelers like [[FreeCAD]], 3D animation packages such as [[3ds Max]], [[Blender (software)|Blender]], [[Cinema 4D]], [[LightWave 3D|Lightwave]], [[Houdini (software)|Houdini]], [[Maya (software)|Maya]], [[modo (software)|modo]], [[MotionBuilder]], [[Autodesk Softimage|Softimage]], the visual effects compositor [[Nuke (software)|Nuke]], 2D imaging programs like [[GIMP]],<ref>{{cite web |url=http://gimp-win.sourceforge.net/faq.html |title=Installers for GIMP for Windows – Frequently Asked Questions |author=<!-- Staff writer(s); no by-line. --> |date=26 July 2013 |access-date=26 July 2013 |url-status=dead |archive-url=https://web.archive.org/web/20130717070814/http://gimp-win.sourceforge.net/faq.html |archive-date=17 July 2013}}</ref> [[Inkscape]], [[Scribus]] and [[Paint Shop Pro]],<ref name="AutoNT-38" /> and [[musical notation]] programs like [[scorewriter]] and [[Capella (notation program)|capella]]. [[GNU Debugger]] uses Python as a [[Prettyprint|pretty printer]] to show complex structures such as C++ containers. [[Esri]] promotes Python as the best choice for writing scripts in [[ArcGIS]].<ref name="AutoNT-39" /> It has also been used in several video games,<ref name="AutoNT-40" /><ref name="AutoNT-41" /> and has been adopted as first of the three available [[programming language]]s in [[Google App Engine]], the other two being [[Java (software platform)|Java]] and [[Go (programming language)|Go]].<ref name="AutoNT-42" />
Many operating systems include Python as a standard component. It ships with most [[Linux distribution]]s,<ref>{{Cite web|url=https://docs.python.org/3/using/unix.html|title=Python Setup and Usage|publisher=Python Software Foundation|access-date=10 January 2020|archive-date=17 June 2020|archive-url=https://web.archive.org/web/20200617143505/https://docs.python.org/3/using/unix.html|url-status=live}}</ref> [[AmigaOS 4]] (using Python 2.7), [[FreeBSD]] (as a package), [[NetBSD]], and [[OpenBSD]] (as a package) and can be used from the command line (terminal). Many Linux distributions use installers written in Python: [[Ubuntu (operating system)|Ubuntu]] uses the [[Ubiquity (software)|Ubiquity]] installer, while [[Red Hat Linux]] and [[Fedora Linux]] use the [[Anaconda (installer)|Anaconda]] installer. [[Gentoo Linux]] uses Python in its [[package management system]], [[Portage (software)|Portage]].
Python is used extensively in the [[information security]] industry, including in exploit development.<ref name="AutoNT-49" /><ref name="AutoNT-50" />
Most of the [[Sugar (software)|Sugar]] software for the [[One Laptop per Child]] XO, developed at [[Sugar Labs]] {{as of|2008|lc=true}}, is written in Python.<ref name="AutoNT-51" /> The [[Raspberry Pi]] [[single-board computer]] project has adopted Python as its main user-programming language.
[[LibreOffice]] includes Python and intends to replace Java with Python. Its Python Scripting Provider is a core feature<ref>{{cite web |title=4.0 New Features and Fixes |publisher=[[The Document Foundation]] |work=LibreOffice.org |year=2013 |url=http://www.libreoffice.org/download/4-0-new-features-and-fixes/ |access-date=25 February 2013 |archive-date=9 February 2014 |archive-url=https://web.archive.org/web/20140209184807/http://www.libreoffice.org/download/4-0-new-features-and-fixes/ |url-status=live}}</ref> since Version 4.0 from 7 February 2013.
==Languages influenced by Python==
Python's design and philosophy have influenced many other programming languages:
* [[Boo (programming language)|Boo]] uses indentation, a similar syntax, and a similar object model.<ref name="AutoNT-90" />
* [[Cobra (programming language)|Cobra]] uses indentation and a similar syntax, and its ''Acknowledgements'' document lists Python first among languages that influenced it.<ref name="AutoNT-91" />
* [[CoffeeScript]], a programming language that cross-compiles to JavaScript, has Python-inspired syntax.
* [[ECMAScript]]/[[JavaScript]] borrowed iterators and [[generator (computer science)|generators]] from Python.<ref name="AutoNT-93" />
* [[GDScript]], a scripting language very similar to Python, built-in to the [[Godot (game engine)|Godot]] game engine.<ref>{{Cite web|url=https://docs.godotengine.org/en/stable/about/faq.html|title=Frequently asked questions|website=Godot Engine documentation|access-date=10 May 2021|archive-date=28 April 2021|archive-url=https://web.archive.org/web/20210428053339/https://docs.godotengine.org/en/stable/about/faq.html|url-status=live}}</ref>
* [[Go (programming language)|Go]] is designed for the "speed of working in a dynamic language like Python"<ref name="AutoNT-94"/> and shares the same syntax for slicing arrays.
* [[Groovy (programming language)|Groovy]] was motivated by the desire to bring the Python design philosophy to [[Java (programming language)|Java]].<ref name="AutoNT-95" />
* [[Julia (programming language)|Julia]] was designed to be "as usable for general programming as Python".<ref name=Julia>{{cite web| title= Why We Created Julia| date= February 2012| website= Julia website| url= https://julialang.org/blog/2012/02/why-we-created-julia| access-date= 5 June 2014| quote= We want something as usable for general programming as Python [...]| archive-date= 2 May 2020| archive-url= https://web.archive.org/web/20200502144010/https://julialang.org/blog/2012/02/why-we-created-julia/| url-status= live}}</ref>
* [[Mojo (programming language)|Mojo]] is currently a non-strict<ref name="Mojo" /><ref>{{Cite web |title=Modular Docs - Why Mojo🔥 |url=https://docs.modular.com/mojo/why-mojo.html |access-date=2023-05-05 |website=docs.modular.com |language=en |quote=Mojo as a member of the Python family [..] Embracing Python massively simplifies our design efforts, because most of the syntax is already specified. [..] we decided that the right long-term goal for Mojo is to provide a superset of Python (i.e. be compatible with existing programs) and to embrace the CPython immediately for long-tail ecosystem enablement. To a Python programmer, we expect and hope that Mojo will be immediately familiar, while also providing new tools for developing systems-level code that enable you to do things that Python falls back to C and C++ for. |archive-date=5 May 2023 |archive-url=https://web.archive.org/web/20230505083518/https://docs.modular.com/mojo/why-mojo.html |url-status=live }}</ref> (aims to be a strict) superset of Python (e.g. still missing classes, and adding e.g. [[struct]]), and is up to 35,000x faster<ref>{{Cite web |last=Spencer |first=Michael |title=What is Mojo Programming Language? |url=https://datasciencelearningcenter.substack.com/p/what-is-mojo-programming-language |access-date=2023-05-05 |website=datasciencelearningcenter.substack.com |date=4 May 2023 |language=en |archive-date=5 May 2023 |archive-url=https://web.archive.org/web/20230505090408/https://datasciencelearningcenter.substack.com/p/what-is-mojo-programming-language |url-status=live }}</ref>{{Better source needed|reason=The benchmark comes from Mojo themselves. Other benchmarks such as https://benchmarksgame-team.pages.debian.net/benchmarksgame/performance/simple.html show python being about 4000x worse then C worst case|date=January 2024}} for some code ([[Mandelbrot set|mandelbrot]], since it is [[embarrassingly parallel]]<!-- the speedup for "scalar C++" is only 5000x, but a parallel version of it or Julia should be able to match Mojo-->), where static typing helps (and <!-- [[Multi-Level Intermediate Representation]] -->[[Intermediate representation#Languages|MLIR]] it is implemented with), and, e.g. 4000 times faster for matrix multiplication.
* [[Nim (programming language)|Nim]] uses indentation and similar syntax.<ref>{{cite web |url=https://www.infoworld.com/article/3157745/application-development/nim-language-draws-from-best-of-python-rust-go-and-lisp.html |title=Nim language draws from best of Python, Rust, Go, and Lisp |first=Serdar |last=Yegulalp |date=16 January 2017 |website=InfoWorld |quote=Nim's syntax is strongly reminiscent of Python's, as it uses indented code blocks and some of the same syntax (such as the way if/elif/then/else blocks are constructed). |access-date=7 June 2020 |archive-date=13 October 2018 |archive-url=https://web.archive.org/web/20181013211847/https://www.infoworld.com/article/3157745/application-development/nim-language-draws-from-best-of-python-rust-go-and-lisp.html |url-status=live}}</ref>
* [[Ruby (programming language)|Ruby]]'s creator, [[Yukihiro Matsumoto]], has said: "I wanted a scripting language that was more powerful than Perl, and more object-oriented than Python. That's why I decided to design my own language."<ref name="linuxdevcenter" />
* [[Swift (programming language)|Swift]], a programming language developed by Apple, has some Python-inspired syntax.<ref>{{cite web |url=http://nondot.org/sabre |title=Chris Lattner's Homepage |publisher=Chris Lattner |first=Chris |last=Lattner |author-link=Chris Lattner |date=3 June 2014 |access-date=3 June 2014 |quote=I started work on the Swift Programming Language in July of 2010. I implemented much of the basic language structure, with only a few people knowing of its existence. A few other (amazing) people started contributing in earnest late in 2011, and it became a major focus for the Apple Developer Tools group in July 2013 [...] drawing ideas from Objective-C, Rust, Haskell, Ruby, Python, C#, CLU, and far too many others to list. |archive-date=22 December 2015 |archive-url=https://web.archive.org/web/20151222150510/http://nondot.org/sabre/ |url-status=live}}</ref>
Python's development practices have also been emulated by other languages. For example, the practice of requiring a document describing the rationale for, and issues surrounding, a change to the language (in Python, a PEP) is also used in [[Tcl]],<ref name="AutoNT-99" /> [[Erlang (programming language)|Erlang]],<ref name="AutoNT-100" /> and Swift.<ref>{{cite web |title=Swift Evolution Process |date=18 February 2020 |website=Swift Programming Language Evolution repository on GitHub |url=https://github.com/apple/swift-evolution/blob/master/process.md |access-date=27 April 2020 |archive-date=27 April 2020 |archive-url=https://web.archive.org/web/20200427182556/https://github.com/apple/swift-evolution/blob/master/process.md |url-status=live}}</ref>
==See also==
{{Portal|Computer programming|Free and open-source software}}
* [[Python syntax and semantics]]
* [[pip (package manager)]]
* [[List of programming languages]]
* [[History of programming languages]]
* [[Comparison of programming languages]]
{{Clear}}
==References==
{{Reflist|30em|refs=
<ref name="faq-created">{{cite web |url=https://docs.python.org/faq/general.html#why-was-python-created-in-the-first-place |title=Why was Python created in the first place? |work=General Python FAQ |publisher=Python Software Foundation |access-date=22 March 2007 |archive-date=24 October 2012 |archive-url=https://web.archive.org/web/20121024164224/http://docs.python.org/faq/general.html#why-was-python-created-in-the-first-place |url-status=live |quote=I had extensive experience with implementing an interpreted language in the ABC group at CWI, and from working with this group I had learned a lot about language design. This is the origin of many Python features, including the use of indentation for statement grouping and the inclusion of very high-level data types (although the details are all different in Python).}}</ref>
<ref name="98-interview">{{cite web |url=http://www.amk.ca/python/writing/gvr-interview |title=Interview with Guido van Rossum (July 1998) |last=Kuchling |first=Andrew M. |work=amk.ca |date=22 December 2006 |access-date=12 March 2012 |url-status=dead |archive-url=https://web.archive.org/web/20070501105422/http://www.amk.ca/python/writing/gvr-interview |archive-date=1 May 2007 |quote=I'd spent a summer at DEC's Systems Research Center, which introduced me to Modula-2+; the Modula-3 final report was being written there at about the same time. What I learned there later showed up in Python's exception handling, modules, and the fact that methods explicitly contain 'self' in their parameter list. String slicing came from Algol-68 and Icon.}}</ref>
<ref name="AutoNT-1">{{cite journal |last=van Rossum |first=Guido |year=1993 |title=An Introduction to Python for UNIX/C Programmers |journal=Proceedings of the NLUUG Najaarsconferentie (Dutch UNIX Users Group) |quote=even though the design of C is far from ideal, its influence on Python is considerable. |citeseerx=10.1.1.38.2023}}</ref>
<ref name="classmix">{{cite web |url=https://docs.python.org/tutorial/classes.html |title=Classes |work=The Python Tutorial |publisher=Python Software Foundation |access-date=20 February 2012 |quote=It is a mixture of the class mechanisms found in C++ and Modula-3 |archive-date=23 October 2012 |archive-url=https://web.archive.org/web/20121023030209/http://docs.python.org/tutorial/classes.html |url-status=live}}</ref>
<ref name="effbot-call-by-object">{{cite web |url=http://effbot.org/zone/call-by-object.htm |title=Call By Object |work=effbot.org |last=Lundh |first=Fredrik |quote=replace "CLU" with "Python", "record" with "instance", and "procedure" with "function or method", and you get a pretty accurate description of Python's object model. |access-date=21 November 2017 |archive-date=23 November 2019 |archive-url=https://web.archive.org/web/20191123043655/http://effbot.org/zone/call-by-object.htm |url-status=live}}</ref>
<ref name="AutoNT-2">{{cite web |url=https://www.python.org/download/releases/2.3/mro/ |title=The Python 2.3 Method Resolution Order |last=Simionato |first=Michele |publisher=Python Software Foundation |quote=The C3 method itself has nothing to do with Python, since it was invented by people working on Dylan and it is described in a paper intended for lispers |access-date=29 July 2014 |archive-date=20 August 2020 |archive-url=https://web.archive.org/web/20200820231854/https://www.python.org/download/releases/2.3/mro/ |url-status=live}}</ref>
<ref name="AutoNT-3">{{cite web |url=https://docs.python.org/howto/functional.html |title=Functional Programming HOWTO |last=Kuchling |first=A. M. |work=Python v2.7.2 documentation |publisher=Python Software Foundation |quote=List comprehensions and generator expressions [...] are a concise notation for such operations, borrowed from the functional programming language Haskell. |access-date=9 February 2012 |archive-date=24 October 2012 |archive-url=https://web.archive.org/web/20121024163217/http://docs.python.org/howto/functional.html |url-status=live}}</ref>
<ref name="pep0238">{{cite web |url=https://www.python.org/dev/peps/pep-0238/ |title=PEP 238 – Changing the Division Operator |first1=Moshe |last1=Zadka |first2=Guido |last2=van Rossum |date=11 March 2001 |work=Python Enhancement Proposals |publisher=Python Software Foundation |access-date=23 October 2013 |archive-date=28 May 2020 |archive-url=https://web.archive.org/web/20200528115550/https://www.python.org/dev/peps/pep-0238/ |url-status=live}}</ref>
<ref name="AutoNT-4">{{cite web |url=https://www.python.org/dev/peps/pep-0255/ |title=PEP 255 – Simple Generators |first1=Neil |last1=Schemenauer |first2=Tim |last2=Peters |first3=Magnus Lie |last3=Hetland |date=18 May 2001 |work=Python Enhancement Proposals |publisher=Python Software Foundation |access-date=9 February 2012 |archive-date=5 June 2020 |archive-url=https://web.archive.org/web/20200605012926/https://www.python.org/dev/peps/pep-0255/ |url-status=live}}</ref>
<ref name="AutoNT-6">{{cite web |url=https://docs.python.org/3.2/tutorial/controlflow.html |title=More Control Flow Tools |work=Python 3 documentation |publisher=Python Software Foundation |access-date=24 July 2015 |archive-date=4 June 2016 |quote=By popular demand, a few features commonly found in functional programming languages like Lisp have been added to Python. With the lambda keyword, small anonymous functions can be created. |archive-url=https://web.archive.org/web/20160604080843/https://docs.python.org/3.2/tutorial/controlflow.html |url-status=live}}</ref>
<ref name="bini">{{cite book |last=Bini |first=Ola |title=Practical JRuby on Rails Web 2.0 Projects: bringing Ruby on Rails to the Java platform |year=2007 |publisher=APress |___location=Berkeley |isbn=978-1-59059-881-8 |page=[https://archive.org/details/practicaljrubyon0000bini/page/3 3] |url-access=registration |url=https://archive.org/details/practicaljrubyon0000bini/page/3}}</ref>
<ref name="AutoNT-7">{{cite web |last=Kuhlman |first=Dave |url=https://www.davekuhlman.org/python_book_01.pdf|title=A Python Book: Beginning Python, Advanced Python, and Python Exercises |at=Section 1.1|url-status=dead |archive-url=https://web.archive.org/web/20120623165941/http://cutter.rexx.com/~dkuhlman/python_book_01.html |archive-date=23 June 2012}}</ref>
<ref name="About">{{cite web |url=https://www.python.org/about |title=About Python |publisher=Python Software Foundation |access-date=24 April 2012 |archive-date=20 April 2012 |archive-url=https://web.archive.org/web/20120420010049/http://www.python.org/about/ |url-status=live}}, second section "Fans of Python use the phrase "batteries included" to describe the standard library, which covers everything from asynchronous processing to zip files."</ref>
<ref name="venners-interview-pt-1">{{cite web |url=http://www.artima.com/intv/pythonP.html |title=The Making of Python |last=Venners |first=Bill |date=13 January 2003 |work=Artima Developer |publisher=Artima |access-date=22 March 2007 |archive-date=1 September 2016 |archive-url=https://web.archive.org/web/20160901183332/http://www.artima.com/intv/pythonP.html |url-status=live}}</ref>
<ref name="timeline-of-python">{{cite web |url=https://python-history.blogspot.com/2009/01/brief-timeline-of-python.html |title=A Brief Timeline of Python |last=van Rossum |first=Guido |date=20 January 2009 |work=The History of Python |access-date=20 January 2009 |archive-date=5 June 2020 |archive-url=https://web.archive.org/web/20200605032200/https://python-history.blogspot.com/2009/01/brief-timeline-of-python.html |url-status=live}}</ref>
<ref name="AutoNT-12">{{cite mailing list |url=https://mail.python.org/pipermail/python-dev/2000-August/008881.html |title=SETL (was: Lukewarm about range literals) |date=29 August 2000 |access-date=13 March 2011 |mailing-list=Python-Dev |last=van Rossum |first=Guido |author-link=Guido van Rossum |archive-date=14 July 2018 |archive-url=https://web.archive.org/web/20180714064019/https://mail.python.org/pipermail/python-dev/2000-August/008881.html |url-status=live}}</ref>
<ref name="newin-2.0">{{cite web |url=https://docs.python.org/whatsnew/2.0.html |title=What's New in Python 2.0 |last1=Kuchling |first1=A. M. |last2=Zadka |first2=Moshe |date=16 October 2000 |publisher=Python Software Foundation |access-date=11 February 2012 |archive-date=23 October 2012 |archive-url=https://web.archive.org/web/20121023112045/http://docs.python.org/whatsnew/2.0.html |url-status=live}}</ref>
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}}
===Sources===
* {{cite web |url=https://wiki.python.org/moin/PythonForArtificialIntelligence |title=Python for Artificial Intelligence |publisher=Python Wiki |date=19 July 2012 |access-date=3 December 2012 |url-status=dead |archive-url=https://web.archive.org/web/20121101045354/http://wiki.python.org/moin/PythonForArtificialIntelligence |archive-date=1 November 2012}}
* {{cite journal |editor-last=Paine |editor-first=Jocelyn |title=AI in Python |journal=AI Expert Newsletter |publisher=Amzi! |date=August 2005 |url=http://www.ainewsletter.com/newsletters/aix_0508.htm#python_ai_ai |access-date=11 February 2012 |archive-url=https://web.archive.org/web/20120326105810/http://www.ainewsletter.com/newsletters/aix_0508.htm#python_ai_ai |archive-date=26 March 2012 |url-status=dead}}
* {{cite web |url=https://pypi.python.org/pypi/PyAIML |title=PyAIML 0.8.5 : Python Package Index |publisher=Pypi.python.org |access-date=17 July 2013}}
* {{cite book |title=Artificial Intelligence: A Modern Approach |last1=Russell |first1=Stuart J. |author-link1=Stuart J. Russell |last2=Norvig |first2=Peter |author-link2=Peter Norvig |name-list-style=amp |edition=3rd |year=2009 |publisher=Prentice Hall |___location=Upper Saddle River, NJ |isbn=978-0-13-604259-4}}
==Further reading==
<!-- THIS IS *NOT* A LIST OF ALL PYTHON BOOKS
According to [[Wikipedia:Further reading]], criteria for inclusion includes:
1. Should clearly qualify as WP:RS, as indicated by reviews and citations to it.
...
5. There should be guidelines on limiting the number of sources.
6. To avoid spam, any book included should have received more than one good review in RS: newspapers and scholarly journals being the norm, and the clear balance of RS reviews should be positive. This would avoid self-publish spamming, POV pushing, and attempts by publishers to get books promoted through inclusion on Wikipedia. At the moment "editorial recommendations" as described in the manual smacks of OR.
7. Neutrality on the part of editors is essential. In terms of major debates, items representing all major positions should be included, with annotations indicating the specific POV of each. We may have to work out rules where topic disputes are irreconcilable.
-->
* {{cite book |last=Downey |first=Allen B. |title=Think Python: How to Think Like a Computer Scientist |edition=<!-- rather show here latest: version 2.0.17 ? --->version 1.6.6 |date=May 2012 |publisher=Cambridge University Press |isbn=978-0-521-72596-5}}
* {{cite news |url=http://www.computerworld.com.au/index.php/id;66665771 |title=The A-Z of Programming Languages: Python |last=Hamilton |first=Naomi |date=5 August 2008 |work=Computerworld |access-date=31 March 2010 |url-status=dead |archive-url=https://web.archive.org/web/20081229095320/http://www.computerworld.com.au/index.php/id%3B66665771 |archive-date=29 December 2008}}
* {{cite book |last=Lutz |first=Mark |title=Learning Python |publisher=O'Reilly Media |year=2013 |edition=5th |isbn=978-0-596-15806-4}}
* {{cite book |last=Summerfield |first=Mark |title=Programming in Python 3 |publisher=Addison-Wesley Professional|year=2009|edition=2nd|isbn=978-0-321-68056-3}}
* {{cite book |last = Ramalho |first = Luciano |title = Fluent Python |url = https://www.thoughtworks.com/insights/books/fluent-python-2nd-edition |date = May 2022 |publisher = O'Reilly Media |isbn = 978-1-4920-5632-4 }}
==External
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