Comparison of programming languages (associative array): Difference between revisions

Revision as of 22:37, 26 July 2020

Revision as of 22:42, 26 July 2020

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Analogously, TreeMap, and other sorted data structures, require that an ordering be defined on the data type. Either the data type must already have defined its own ordering, by implementing the {{Javadoc:SE|java/lang|Comparable}} interface; or a custom {{Javadoc:SE|java/util|Comparator}} must be provided at the time the map is constructed. As with HashMap above, the relative ordering of keys in a TreeMap should not change once they have been inserted into the map.

=== [[JavaScript]] ===

[[JavaScript]] (and its standardized version:, [[ECMAScript]]) is a [[Prototype-based programming|prototype-based]] [[Object-oriented programming|object-oriented]] language.

====Map and WeakMap====

Modern JavaScript handles associative arrays, using Map and WeakMap classes. A map does not contain any keys by default. It only contains what is explicitly put into it. The keys and values can be any valuetype (including functions, objects, or any primitive).

=====''Creation''=====

Modern JavaScript handles associative arrays using Map and WeakMap classes. A map does not contain any keys by default. It only contains what is explicitly put into it. The keys and values can be any value (including functions, objects, or any primitive).

=====''Creation''=====

A map can be initialized with all items during construction:

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</syntaxhighlight>

=====''Access by key''=====

Accessing an element of the map can be done with the "get" method:

Accessing an element of the map can be done with the get method:

<syntaxhighlight lang=JavaScript>