Introducing Python, 3rd Edition

Chapter 9. Sets and Dictionaries

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If a word in the dictionary were misspelled, how would we know?

Steven Wright

Dictionaries are particularly useful key:value data structures, and you’ll see them used everywhere in Python. Sets are just bags of unique keys, anbd are also often vary handy.

Dictionaries

A dictionary is similar to a list, but the order of items doesn’t matter, and they aren’t selected by an offset such as 0 or 1. Instead, you specify a unique key to associate with each value. This key is often a string, but it can actually be any of Python’s immutable types: Boolean, integer, float, tuple, string, and others that you’ll see in later chapters. Dictionaries are mutable, so you can add, delete, and change their key-value elements. If you’ve worked with languages that support only arrays or lists, you’ll love dictionaries.

Note

In other languages, dictionaries might be called associative arrays, hashes, or hashmaps ...