Substring: Difference between revisions

Revision as of 15:49, 26 November 2022

Revision as of 20:53, 2 January 2023

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{{About|the definition of a substring|the computer function which performs this operation|String functions (programming)}}

{{Distinguish|text=[[subsequence]], a generalization of substring}}

[[File:Substring.png|thumb|"''string''" is a substring of "''substring''"]]

In [[Formal language|formal language theory]] and [[computer science]], a '''substring''' is a contiguous sequence of [[Character (computing)|character]]s within a [[String (computer science)|string]]<!-- Needs a citation. -->.{{Citation needed|date=July 2021}} For instance, "''the best of''" is a substring of "''It was the best of times''". In contrast, "''Itwastimes''" is a subsequence of "''It was the best of times''", but not a substring.

'''Prefixes''' and '''suffixes''' are special cases of substrings. A prefix of a string <math>S</math> is a substring of <math>S</math> that occurs at the beginning of <math>S</math>; likewise, a suffix of a string <math>S</math> is a substring that occurs at the end of <math>S</math>.

The substrings of the string "''apple''" would be:

"''a''", "''ap''", "''app''", "''appl''", "''apple''",

"''p''", "''pp''", "''ppl''", "''pple''",

"''pl''", "''ple''",

"''l''", "''le''"

"''e''", and ""

(note the [[empty string]] at the end).