Python List remove() Method

Python list remove() method removes a given element from the list.

Example:

['a', 'c']

List remove() Syntax

list_name.remove(obj) 

Parameter

• obj: object to be removed from the list 

Returns

The method does not return any value but removes the given object from the list.

Exception

If the element doesn’t exist, it throws ValueError: list.remove(x): x not in list exception.

Note: It removes the first occurrence of the object from the list. 

What is Python list remove() Function

The list remove() function in Python removes the first occurrence of a given item from the list. It make changes to the current list.

It only takes one argument that is the element you want to remove and if that element is not present in the list, it gives ValueError.

It is very useful in removing incorrect values from a list, without affecting the rest of the list.

How to Use List remove() Method

remove() function is a very important function of lists. It is very easy to use, just call the function with a list object and pass the value you want to remove as a parameter. Let’s look at an example to understand how to remove an element from a list:

More Examples of list remove()

Let’s see some of the most common use-case scenarios with the list remove() function to have a deep understanding of the topic.

• Remove an element from the list 
• Deleting Element that doesn’t Exist
• Remove Duplicates from List in Python
• Remove all Occurrences of a value from a List
• Removing a nested list element from a list
• Removing elements from a list based on a condition
• Removing an Element by Value from a List
• Removing elements from a list using the Filter function

1. Remove an element from the list in Python

In this example, we are showing how we can use the remove() function with the Python list. Remove function removes the specified element’s first occurrence in the list.

[2, 1, 1, 4, 5]
['b', 'c', 'd']

Time complexity: for the first list removal: O(n)
Time complexity: for the second list removal: O(1)
Space complexity: O(1) for both cases.

2. Deleting Element that doesn’t Exist

In this example, we are removing the element  ‘e’ which does not exist.

Output

Traceback (most recent call last):
  File "/home/e35b642d8d5c06d24e9b31c7e7b9a7fa.py", line 8, in 
    list2.remove('e') 
ValueError: list.remove(x): x not in list

3. Remove Duplicates from the List in Python

In this example, we are removing the element which comes multiple times in the list.

['a', 'b', 'c', 'd', 'e', 'd']

Time complexity: O(n) 
Space complexity: O(1)

Note: If a list contains duplicate elements, it removes the first occurrence of the object from the list. 

4. Remove all Occurrences of a value from a List

Let’s see how to remove all the occurrences of a value from a list.

Example 1: Remove all the 1’s from the list and print the list.

In this example, we remove 1 from the list until all 1 is removed.

[2, 3, 4, 4, 5]

Time complexity: O(n^2) 
Space complexity: O(1)

Example 2: Given a list, remove all the 2’s from the list using in keyword 

In this example, we remove 2 from the list until all the 2 are removed.

[1, 3]

Time complexity: O(n^2)
Space complexity: O(1) – The space complexity is O(1) since we are only modifying the existing list and not creating any additional data structures proportional to the input size.

5. Removing a nested list element from a list

In this example, we are removing a list from a 2d List.

[[1, 2], [5, 6]]

Time complexity: O(n) 
Space complexity: O(1)

6. Removing elements from a list based on a condition using a list comprehension

In this example, we are moving numbers from the list using list comprehension.

[1, 2, 4, 5]

Time complexity: O(n) 
Space complexity: O(1)

7. Removing an Element by Value from a List

This example demonstrates how to remove a specific element (in this case, ‘3’) from a list using the remove() method. It first checks if the element exists in the list before attempting to remove it.

Updated list: [1, 2, 4, 5]

Time complexity: O(n) 
Space complexity: O(1)

8. Removing elements from a list using the Filter function

In this example, we are using the lambda function to check the condition and filter out the data from the list.

[1, 2, 4, 5]

Time complexity: O(n) 
Space complexity: O(n)

We have discussed the definition, uses and examples of the list remove() method in Python. The list remove function is an important list operating function and is used to remove a particular value from the list.

Read More List Methods

Similar Reads:

• How to remove an item from the List in Python
• Remove first element of list
• Ways to remove particular List element in Python
• Remove given element from the list

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