Python Lists

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

Lists are one of the most commonly used data types in Python.

Creating a List

Lists are created using square brackets [].

Example:

fruits = ["Apple", "Banana", "Mango"]

print(fruits)

Output:

['Apple', 'Banana', 'Mango']

List Items

List items:

• Are ordered
• Are changeable
• Allow duplicate values

Example:

fruits = ["Apple", "Banana", "Apple"]

print(fruits)

Output:

['Apple', 'Banana', 'Apple']

List Length

Use the len() function to find the number of items in a list.

Example:

fruits = ["Apple", "Banana", "Mango"]

print(len(fruits))

Output:

3

List Data Types

A list can contain different data types.

Example:

items = ["John", 25, True, 10.5]

print(items)

Output:

['John', 25, True, 10.5]

Access List Items

List items are indexed starting from 0.

Example:

fruits = ["Apple", "Banana", "Mango"]

print(fruits[0])

Output:

Apple

Negative Indexing

Negative indexing starts from the end.

Example:

fruits = ["Apple", "Banana", "Mango"]

print(fruits[-1])

Output:

Mango

Range of Indexes

You can access a range of items using slicing.

Example:

fruits = ["Apple", "Banana", "Mango", "Orange"]

print(fruits[1:3])

Output:

['Banana', 'Mango']

Change List Items

Lists are changeable.

Example:

fruits = ["Apple", "Banana", "Mango"]

fruits[1] = "Orange"

print(fruits)

Output:

['Apple', 'Orange', 'Mango']

Add List Items

Use the append() method to add an item.

Example:

fruits = ["Apple", "Banana"]

fruits.append("Mango")

print(fruits)

Output:

['Apple', 'Banana', 'Mango']

Insert Items

Use the insert() method to add an item at a specific position.

Example:

fruits = ["Apple", "Mango"]

fruits.insert(1, "Banana")

print(fruits)

Output:

['Apple', 'Banana', 'Mango']

Remove List Items

Use the remove() method.

Example:

fruits = ["Apple", "Banana", "Mango"]

fruits.remove("Banana")

print(fruits)

Output:

['Apple', 'Mango']

Remove by Index

Use the pop() method.

Example:

fruits = ["Apple", "Banana", "Mango"]

fruits.pop(1)

print(fruits)

Output:

['Apple', 'Mango']

Loop Through a List

Example:

fruits = ["Apple", "Banana", "Mango"]

for fruit in fruits:
    print(fruit)

Output:

Apple
Banana
Mango

Check if Item Exists

Use the in keyword.

Example:

fruits = ["Apple", "Banana", "Mango"]

print("Apple" in fruits)

Output:

True

Copy a List

Example:

fruits = ["Apple", "Banana"]

new_list = fruits.copy()

print(new_list)

Output:

['Apple', 'Banana']

Join Lists

Example:

list1 = ["Apple", "Banana"]
list2 = ["Mango", "Orange"]

list3 = list1 + list2

print(list3)

Output:

['Apple', 'Banana', 'Mango', 'Orange']

List Constructor

You can also create a list using the list() constructor.

Example:

fruits = list(("Apple", "Banana", "Mango"))

print(fruits)

Output:

['Apple', 'Banana', 'Mango']

Summary

• Lists store multiple items in a single variable.
• Lists are ordered, changeable, and allow duplicates.
• Use indexing to access items.
• Use append() and insert() to add items.
• Use remove() and pop() to delete items.
• Use loops to iterate through lists.
• Use len() to get the number of items.
• Lists can contain different data types.