Python List clear()

Python offers you a range of built-in functions to remove elements from a list, such as pop(), remove(), del, etc. However, if you want to remove all the items in a list at once, you can use the Python clear list method.

clear() Parameters

The clear() method has the simple syntax of:

                    

list.clear()

                

Unlike other deleting functions, clear() does not accept any parameters.

Return Value from clear()

The method also does not return any value and only removes all the elements in a list.

Example of how clear() method works

Let us look at an example where we will clear all the items in the list: hobbies.

                    

# create list
hobbies = ['swimming', 'singing', 'dancing', 'running', 'painting']
hobbies.clear()

print ('List:', hobbies)

                

Output:

                    

List: []

                

Example of emptying the List Using del

Although the Python clear list function is convenient, it is not available in Python 2 or Python 3.2 and below. In these versions, we use the del keyword.

                    

# hobbies list
hobbies = ['swimming', 'singing', 'dancing', 'running', 'painting']
del hobbies[:]

print ('List:', hobbies)

                

Output:

                    

List: []

                

Questions and Answers

Q1. How do you clear a list in Python?

You can clear a list in Python by using the Python clear() list method.

Let us see how:

                    

# creating a fruits list
fruits = ['apple', 'grapes', 'grapes', 'banana', 'guava', 'grapes', 'banana']

# clearing all the elements using the clear() method
fruits. clear()

print ('Fruits:', fruits)

                

Output:

                    

Fruits: []

                

Q2. What does clear() do in Python?

Python clear for lists is a built-in function that allows you to remove all the items in a list at once. It neither accepts any parameters nor returns a value. It follows the syntax:

                    

list.clear()

                

Q3. How do you empty a list?

Apart from using the Python clear list function, you can also empty a list using the del keyword. Usually, we pass the index values of the list element to delete them through del or set a range of indexes using a colon to delete multiple items.

However, to empty the complete list, we enclose the colon in [] without index values. Let us see how this through an example:

                    

# creating a flowers list 
flowers = ['rose', 'lily', 'tulip', 'lotus',  'marigold']

# clearing all the elements using the del keyword
del fruits [ : ]

print('Flowers:', flowers)

                

Output:

                    

Flowers: []

                

Q4. How do I remove all elements from a list?

You can remove all the elements from a list through three methods:

1. By using the clear() function.

2. By using the del keyword.

3. By using the slice assignment.

Let us see how:

                    

# creating name list
name = ['Bob', 'Phil', 'Alice', 'Noah', 'Jill', 'Jack', 'David']

# removing all elements using clear()
name.clear()
print ('Names list:',name)

# creating subjects list
subject = ['Science', 'Maths', 'English', ' Social']

# removing all elements using del
del subject [ : ]
print ('Subjects list:', subject)

# creating number list
num = [43, 54, 8, 3, 345, 34,]
x = num
print (num)	# prints [43, 54, 8, 3, 345, 34,]

num[ : ] = []	# assigning an empty list to num
print ('Numbers list:', num)	# prints []
print (x)		# prints []

                

Output:

                    

Names list: []
Subjects list: []
[43, 54, 8, 3, 345, 34]
Numbers list: []
[]

                

In the final example, we cleared the entire num list by assigning an empty list to the slice, i.e, num[ : ] = [].