Python List insert()

The insert() method inserts an item to the list at a specified index. Here's a quick example.

vowel = ['a', 'e', 'i', 'u']

# 'o' is inserted at index 3 (4th position)
vowel.insert(3, 'o')

print('List:', vowel)

# Output: List: ['a', 'e', 'i', 'o', 'u']

insert() Syntax

The syntax of insert() is:

my_list.insert(index, item)

Arguments

index - Index where item is to be inserted.

item - Item to be inserted.

Return Value

The insert() method doesn't return any value (it returns None).

Example: Inserting a String

words = ["apple", "ball", "dog"]

# Insert "cat" at index 2 (third position)
words.insert(2, "cat")

print(f"Words = {words}")

Output

Words = ['apple', 'ball', 'cat', 'dog']

Example: Inserting a Dictionary

words = [{"a": "apple"}, {"b": "ball"}, {"d": "dog"}]

# Insert {"c": "cat"} at index 2 (third position)
words.insert(2, {"c": "cat"})

print(f"Words = {words}")

Output

Words = [{'a': 'apple'}, {'b': 'ball'}, {'c': 'cat'}, {'d': 'dog'}]

Example: Negative Index

Using negative index in insert() counts items from the end. Item is placed before the item at that negative position.

words = ["apple", "ball", "dog"]

# "cat" is inserted before item at index -1
words.insert(-1, "cat")

print(words)

Output

Words = ['apple', 'ball', 'cat', 'dog']

Also Read:

• Python List append() - Insert an item at the end of list.
• Python List extend() - Insert all items of an iterable to end of list.