What is insert () in python?

In this tutorial, we will learn about the Python List insert() method with the help of examples.

The insert() method inserts an element to the list at the specified index.

Example

# create a list of vowels
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']


Syntax of List insert()

The syntax of the insert() method is

list.insert(i, elem)

Here, elem is inserted to the list at the ith index. All the elements after elem are shifted to the right.


insert() Parameters

The insert() method takes two parameters:

  • index - the index where the element needs to be inserted
  • element - this is the element to be inserted in the list

Notes:

  • If index is 0, the element is inserted at the beginning of the list.
  • If index is 3, the index of the inserted element will be 3 (4th element in the list).


Return Value from insert()

The insert() method doesn't return anything; returns None. It only updates the current list.


Example 1: Inserting an Element to the List

# create a list of prime numbers
prime_numbers = [2, 3, 5, 7]

# insert 11 at index 4 prime_numbers.insert(4, 11)

print('List:', prime_numbers)

Output

List: [2, 3, 5, 7, 11]

Example 2: Inserting a Tuple (as an Element) to the List

mixed_list = [{1, 2}, [5, 6, 7]]

# number tuple
number_tuple = (3, 4)

# inserting a tuple to the list mixed_list.insert(1, number_tuple)

print('Updated List:', mixed_list)

Output

Updated List: [{1, 2}, (3, 4), [5, 6, 7]]

Python List insert() method inserts a given element at a given index in a list using Python. 

Python List insert() Syntax

Syntax: list_name.insert(index, element)

Parameters: 

  • index: the index at which the element has to be inserted.
  • element: the element to be inserted in the list.

Returns: Does not return any value.

Python List insert() Example

Python insert() methods with string in Python.

Python3

lis = ['Geeks', 'Geeks']

lis.insert(1, "For")

print(lis)

Output:

['Geeks', 'For', 'Geeks']

Example 1: Inserting an Element into the List

Here, we are inserting 10 at the 5th position(4th index) in a Python list.

Python3

list1 = [ 1, 2, 3, 4, 5, 6, 7

list1.insert(4, 10

print(list1) 

Output: 

[1, 2, 3, 4, 10, 5, 6, 7]

Example 2: Error of insert() Method

Here, we are inserting 1 at the 10th position in a Python list, we will get an error, If we try to insert anything in a string because the string doesn’t have attribute insert().

Python3

string = "1234567"

string.insert(10, 1)

print(string)

Output: 

Traceback (most recent call last):
  File "/home/2fe54bd8723cd0ae89a17325da8b2eb5.py",
   line 7, in 
    string.insert(10, 1)
AttributeError: 'str' object has no attribute 'insert'

Example 3: Insertion in a List Before any Element

Here, we are inserting 13 at the 3rd position before 3 in a Python list.

Python3

list1 = [ 1, 2, 3, 4, 5, 6 ]

element = 13 

beforeElement = 3 

index = list1.index(beforeElement) 

list1.insert(index, element) 

print(list1)

Output: 

[1, 2, 13, 3, 4, 5, 6]

Example 4: Inserting a Tuple into the List

Here we are inserting a tuple in a list using the insert() function in Python.

Python3

list1 = [ 1, 2, 3, 4, 5, 6 ]

num_tuple = (4, 5, 6)

list1.insert(2, num_tuple)

print(list1)

Output: 

[1, 2, (4, 5, 6), 3, 4, 5, 6]

What is use of insert () method in list?

The insert() method inserts an element to the list at the specified index.

What does the insert function do?

The INSERT( ) function inserts specified characters or spaces into a character string, beginning at a specified position in the string.

What is the difference between Insert () and append () method in Python?

The only difference between append() and insert() is that insert function allows us to add a specific element at a specified index of the list unlike append() where we can add the element only at end of the list.

What is insert () and append () function give examples?

Difference between Append, Extend and Insert.