dict

A dictionary is a mapping type data structure that associates hashable keys to values

keys

Keys can include immutable values such as numbers, str, tuples, or frozensets, but must be hashable and unique across the dictionary.

values

Values can be of any or multiple data type(s) or structrues, including other dictionaries, built-in types, custom types, or even objects like functions or classes.

Dictionaries enable the retrieval of a value given the key.

dict vs list / array

Compared to searching for a value in an array or list (without knowing the index position), a dict uses significantly more space in memory, but has significantly more rapid retrieval. Dictionaries are especially useful in scenarios where the collection of items is large and must be accessed and/or updated frequently.

Declaration

Declaring a dict decclares an empty dictionary using the literal form:

dict = {}

Initialization

A simple dict can be initialized using the literal form: