Associative array

An associative array stores values under keys and retrieves them by key rather than by position. It is also called a map, dictionary, or symbol table in different contexts.

Hash table: A data structure that maps keys to positions in an array using a hash function. Many associative arrays use hashing to turn keys into locations for fast lookup.
Key–value pair: A pairing of a key, used for identification, with a value associated with it. Each associative-array entry binds a lookup key to its stored value.
Python dictionary: Python's built-in mutable mapping type, which associates hashable keys with values. It is Python's standard associative-array type, with insertion-ordered iteration.
Array data type: A collection whose elements are accessed by integer indices, usually corresponding to positions. Arrays select elements by position, while associative arrays select them by key.
Hash function: A function that converts input data into a fixed-size value used to organize or identify data. It maps associative-array keys to candidate storage locations in hash-table implementations.
Key (computing): An identifier used to locate or distinguish an entry in a data structure. The key, rather than an entry's position, selects an associative-array value.
JavaScript object: A JavaScript object is a collection of properties, each pairing a string or symbol key with a value. Objects often serve as key-value collections, though their property semantics differ from dedicated maps.
Ordered map: A map that preserves a defined order among its entries, often insertion order. It adds predictable iteration order to key-based lookup.
Collision resolution: Methods for handling distinct keys that map to the same location in a hash table. Hash-based associative arrays need a policy when different keys share a slot.
Value (computer science): A piece of data that can be stored, computed, or returned by a program. Values are the payloads retrieved after an associative-array key is matched.

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