What does "dictionary" mean in programming?

dictionary is one of the most common terms in software development. This guide explains what it means, how it is used in practice, and why it matters, with real examples from the developer world.

Definition

A data structure that stores key-value pairs. Dictionaries provide fast lookups by key. They are called 'dict' in Python, 'HashMap' in Java, and 'object' or 'Map' in JavaScript.

Example

"Use a dictionary to map each user ID to their profile data for O(1) lookup."

Related terms

hash
array
list
object
JSON

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