Python Lists

mylist = ["apple", "banana", "cherry"]

Lists are used to store multiple items in a single variable.

Tuple, Set, and Dictionary, all with different qualities and usage. Lists are created using square brackets:

thislist = ["apple", "banana", "cherry"]

List items are ordered, changeable, and allow duplicate values. List items are indexed, the first item has index [0], the second item has index [1] etc.

When we say that lists are ordered, it means that the items have a defined order, and that order will not change. If you add new items to a list, the new items will be placed at the end of the list.

There are some list methods that will change the order, but in general: the order of the items will not change.

The list is changeable, meaning that we can change, add, and remove items in a list after it has been created.

Since lists are indexed, lists can have items with the same value:

thislist = ["apple", "banana", "cherry", "apple", "cherry"]

To determine how many items a list has, use the len() function:

Print the number of items in the list: thislist = ["apple", "banana", "cherry"]

List items can be of any data type:

String, int and boolean data types: list1 = ["apple", "banana", "cherry"] list2 = [1, 5, 7, 9, 3] list3 = [True, False, False] A list can contain different data types:

A list with strings, integers and boolean values: list1 = ["abc", 34, True, 40, "male"] type() From Python's perspective, lists are defined as objects with the data type 'list': <class 'list'>

What is the data type of a list? mylist = ["apple", "banana", "cherry"]

It is also possible to use the list() constructor when creating a new list.

constructor to make a List:

There are four collection data types in the Python programming language: List is a collection which is ordered and changeable. Allows duplicate members. Tuple is a collection which is ordered and unchangeable. Allows duplicate members. Set is a collection which is unordered, unchangeable*, and unindexed. No duplicate members. Dictionary is a collection which is ordered** and changeable. No duplicate members.

**As of Python version 3.7, dictionaries are ordered. In Python 3.6 and earlier, dictionaries are unordered. When choosing a collection type, it is useful to understand the properties of that type. Choosing the right type for a particular data set could mean retention of meaning, and, it could mean an increase in efficiency or security.