Collections

Collections are groups of items. Python supports several types of collections. Three of the most common are dictionaries, lists and arrays.

Lists

Lists are a collection of items. Lists can be expanded or contracted as needed, and can contain any data type. Lists are most commonly used to store a single column collection of information, however it is possible to nest lists

Arrays

Arrays are similar to lists, however are designed to store a uniform basic data type, such as integers or floating point numbers.

Dictionaries

Dictionaries are key/value pairs of a collection of items. Unlike a list where items can only be accessed by their index or value, dictionaries use keys to identify each item.