Python Program to clear a list
In this tutorial, we will learn how to clear a list in Python. Clearing a list simply means deleting all the elements of that list. There are many methods to clear a list in Python, we will be discussing all those methods in this tutorial.
Input: [3, 8, 1, 4, 9]
Output: [ ]
Approach To Clear a List in Python
In Python, there are 4 ways for clearing a list:
- using del() method
- using clear() method
- by re-initializing the list
- using *=0 expression
We will look at each approach in detail.
Approach 1: Clear by using del
In this approach, we will use the del() method, del() is used to clear all the list elements within a range. If we don’t give a range, all the elements in the list will be deleted.
Algorithm
Follow the algorithm to understand the approach better:
Step 1- Initialise a list
Step 2- Print the existing list
Step 3- Delete all list elements by giving [:] as range
Step 4- Print list after deletion
Python Program 1
Look at the program to understand the implementation of the above-mentioned approach.
#clearing a list
#using del()
list = ['Studytonight', 1, 2, 3]
print("Existing list: ",list)
# Removing all elements
del list[:]
print("After deleting all elements: ")
print(list)
Existing list: ['Studytonight', 1, 2, 3]
After deleting all elements:
[]
Approach 2: clear() method
In this approach, we will use the clear() method. It is a predefined function in the Python library that completely empties the list.
Algorithm
Follow the algorithm to understand the approach better
Step 1- Initialise a list
Step 2- Print the existing list
Step 3- Delete the list using list.clear() function
Step 4- Print list after deletion
Python Program 2
Look at the program to understand the implementation of the above-mentioned approach
#clearing a list
#using clear()
list = ['Studytonight', 1, 2, 'list']
print("Existing list: ",list)
# Removing all elements
list.clear()
print("After deleting all elements: ")
print(list)
Existing list: ['Studytonight', 1, 2, 'list']
After deleting all elements:
[]
Approach 3: Clear by using re-initialise list
In this approach, we will re-initialize the list by assigning an empty list to it.
Algorithm
Follow the algorithm to understand the approach better.
Step 1- Initialise a list
Step 2- Print the existing list
Step 3- Re-initialise an empty list to the original list
Step 4- Print list after deletion
Python Program 3
Look at the program to understand the implementation of the above-mentioned approach.
#clearing a list
#re initialise
list = ['Study','tonight', 1, 2]
print("Existing list",list)
# Removing all elements
list = []
print("After deleting all elements")
print(list)
Existing list ['Study', 'tonight', 1, 2]
After deleting all elements
[]
Approach 4: using *=0
In this approach, we just assign 0 to all elements in the list which makes the list empty. The * is a character representing all elements. This is a lesser-known method for clearing a list.
Syntax- list_name *= 0
Algorithm
Follow the algorithm to understand the approach better
Step 1- Initialise a list
Step 2- Print the existing list
Step 3- Delete list by assigning 0 to all elements
Step 4- Print list after deletion
Python Program 4
Look at the program to understand the implementation of the above-mentioned approach.
#clearing a list
#using *0
list = ['Study','tonight', 1, 2, 3]
print("Existing list",list)
# Removing all elements
list *= 0
print("After deleting all elements")
print(list)
Existing list ['Study', 'tonight', 1, 2, 3]
After deleting all elements
[]
Conclusion
In this tutorial, we have discussed all the different methods for clearing a list. All the approaches are efficient for clearing a list.
