Data containers

Data must often be grouped, ordered, counted, and sorted. Python has a number of built-in data "containers", which can be used for each and all of these needs. Lists, tuples, sets, and dictionaries are the main data containers, and can be created and manipulated without the need to import any libraries.

For array types like lists and tuples, the order of the data is very important for retrieval. Data containers like dictionaries "map" data using a "key-value" retrieval system, where the "key" is mapped or connected to the "value". In dictionaries, the order of the data is not important. For all mutable data containers, sets can be used to retrieve all unique values within a data container such as a list.