Delete All Elements Of A List In Python

In python, we use lists in almost every program. We have already discussed ways to compare two lists and to reverse a list in python. In this article, we will discuss different ways to delete all the elements of a list in python.

Delete All Elements Of A List In Python Using The clear() Method

The pop() method is used to delete the last element of a list. When invoked on a list, the pop() method returns the last element of the list and deletes it from the list. We can use the while loop and the pop() method to remove all the elements of the list. 

For this, we can keep invoking the pop() method on the list inside the while loop until the list becomes empty.  Once the list becomes empty, the while loop will stop its execution and we will get a list that has no elements. You can observe this in the following program.

myList = [1, 2, 3, 4, 5, 6, 7, 8, 9]
print("The original list is:")
print(myList)
# deleting elements using the pop() method
while myList:
    myList.pop()
print("List after deleting all the elements:",myList)

Output:

The original list is:
[1, 2, 3, 4, 5, 6, 7, 8, 9]
List after deleting all the elements: []

Instead of using the pop() method several times, we can use the clear() method to delete all the elements from a list. The clear() method, when invoked on a list, deletes all the elements of the list. 

myList = [1, 2, 3, 4, 5, 6, 7, 8, 9]
print("The original list is:")
print(myList)
# deleting elements using the clear() method
myList.clear()
print("List after deleting all the elements:",myList)

Output:

The original list is:
[1, 2, 3, 4, 5, 6, 7, 8, 9]
List after deleting all the elements: []

Delete All Elements Of A List In Python Using The del Statement

The del statement is used to delete an object in python. We can also use the del statement to remove the elements of a list. For this, we will create a slice of the list that contains all the elements. After that, we will delete the slice. As the slice contains references to the elements in the original list, all the elements in the original list will be deleted and we will get an empty list. You can do it as follows.

myList = [1, 2, 3, 4, 5, 6, 7, 8, 9]
print("The original list is:")
print(myList)
# deleting elements using the del method
del myList[:]
print("List after deleting all the elements:", myList)

Output:

The original list is:
[1, 2, 3, 4, 5, 6, 7, 8, 9]
List after deleting all the elements: []

Delete All Elements Of A List In Python Using The * Operator

This is one of the least used ways to remove elements from a list in Python. You might be knowing that multiplying a list to any number N repeats the elements of the list N times. In the same way, when we multiply a list to 0, all the elements of the list are deleted. So, we can multiply the given list with 0 to remove all of its elements as follows.

myList = [1, 2, 3, 4, 5, 6, 7, 8, 9]
print("The original list is:")
print(myList)
# deleting elements using *
myList = myList * 0
print("List after deleting all the elements:", myList)

Output:

The original list is:
[1, 2, 3, 4, 5, 6, 7, 8, 9]
List after deleting all the elements: []

Conclusion

In this article, we have discussed four different ways to delete all the elements of a list in python. To know more about lists in python, you can read this article on list comprehension. You might also like this article on how to get the last element of a list in python.