Remove an element from a python list (pop, del, clear, remove)

In this post, you will learn several methods to delete or remove elements from the python list. method like pop(), clear(), remove() or del keyword.

1. Pop() : remove elements by their index
2. Del: remove element by index or remove multiple elements
3. Clear(): remove all elements from the list
4. Remove(): remove an element by its value.
5. By using the list comprehension method 

Remove elements by their index by using the pop() method

Pop() is an inbuilt method, you can delete an element from a list by the passing index of the element. Before passing the index first check whether an index is valid or not, if an index is not valid then pop() method will raise IndexError.

If you don’t pass the index position in the pop() method then it will remove the last element by default.

syntax of pop():

always remember index position is start from 0. So if there are 5 elements in a list then the index will be 0 to 4.

my_list=['start','learn', 'study', 'program', 'code',5, 'python', 2]
print("before removing list:",my_list)
element=my_list.pop(2)
print("deleted element is:",element)
print("After removing element list become",my_list)

#delete a range of element by using pop()
#by using for loop
my_list1=['st', 'learn', 'sty', 'pr', 'code', 'strr', 'pyth', 20]
print("before deleting list:",my_list1)

delete=[1, 3, 4, 6] # all index which you want to delete
for i in delete:
    my_list1.pop(2)

print("list after deleting range of element",my_list1)

before removing list: ['start', 'learn', 'study', 'program', 'code', 5, 'python', 2]
deleted element is: study
after removing element list become ['start', 'learn', 'program', 'code', 5, 'python', 2]

before deleting list: ['st', 'learn', 'sty', 'pr', 'code', 'strr', 'pyth', 20]
list after deleting range of element ['st', 'learn', 'pyth', 20]

Use of del for removing item by index

Del is another way to delete an element from a list by index, but by using del you can delete a range of elements

list1=[1,2,3,4]
del list1[0]
print("list1 after delete:",list1)

#output:- list1 after delete: [2, 3, 4]

By using the del keyword, you can delete multiple elements.

# delete range of element
list1=[1,2,3,4]
del list1[1:3]
print("After removing multiple items", list1)

#output:-After removing multiple items [1, 4]

Remove all elements in the list by using clear() method

clear() method doesn't remove individuals element, it removes all elements present in the list and makes it an empty list without deleting the list variable. 

see the below example of how the clear() method removes all elements.

my_list=[1, 2, 'dam', 4, 5, 6, 7, 8, 9]
my_list.clear()
print(my_list)

#output:- []

Remove a element by value: remove()

remove() method is used to delete the first occurrence of numbers or strings mentioned in its arguments.

list1=['bob', 'jack', 'alice', 'robato', 'top']
list1.remove('bob')
print(list1)

#output:- ['jack', 'alice', 'robato', 'top']

If the list contains more than one specified value in an argument then only the first occurrence of the specified value gets deleted.

In the below example alice contains two times in a list but only the first occurrence is deleted.

list1=['alice', 'jack', 'bob', 'alice', 'robato', 'rain']
list1.remove('alice')
print(list1)

#output:- ['jack', 'bob', 'alice', 'robato', 'rain']

if the specified value in an argument is not available in a list then it will raise ValueError.

list1=['all', 'albert', 'jack', 'bob', 'first', 'rain']
list1.remove('rabato')
print(list1)

#output:- ValueError: list.remove(x): x not in list

remove elements by using list comprehension

List comprehensions are used for creating a new list based on the value of an existing list. It basically filters your old list and makes a new list. For example, you can separate all odd elements from a list by using List comprehensions.

list1 = list(range(10))
print(list1)
#output:-[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]

lc=[i for i in list1 if i % 2 != 0]
print("odd value",lc)
#output:-odd value [1, 3, 5, 7, 9]