A list is one of the data structures in Python that you can use to store a collection of variables.

In some cases, you have to iterate through and perform an operation on the elements of a list. But you can't loop/iterate through a list if it has no elements in it.

In this article, you'll learn how to check if a list is empty by:

  • Using the not operator.
  • Using the len() function.
  • Comparing the list to an empty list.

How To Check if a List Is Empty in Python Using the not Operator

The not operator in Python is used for logical negation. Here's an example:

x = True
y = False

print(not x)  # Output: False
print(not y)  # Output: True

not returns true when an operand is false, and false if an operand is true.

You can check if a collection is empty using the logic above. Here's how:

people_list = [] 

if not people_list:
    print("Your list is empty")
else:
    print("Your list is not empty")
    
# Your list is empty

In the code above, we used an if statement and the not operator to check if the people_list was empty.

How To Check if a List Is Empty in Python Using the len() Function

You can use the len() function in Python to return the number of elements in a data structure.

Here's an example: 

people_list = ["John", "Jane", "Jade", "Doe"] 

print(len(people_list))
# 4

Using the len() function, we printed the length of the people_list list which had four elements.

You can also get the length of an empty list:

people_list = [] 

print(len(people_list))
# 0

Now that we know that the length of an empty list is 0, we use it to check if a list is empty:

people_list = [] 

if len(people_list) == 0:
    print("Your list is empty")
else:
    print("Your list is not empty")

# Your list is empty

How To Check if a List Is Empty in Python By Comparing To an Empty List

An interesting way to check if a list is empty is by comparing it to another empty list. That is:

people_list = [] 

if people_list == []:
    print("Your list is empty")
else:
    print("Your list is not empty")

# Your list is empty

In the example above, we compared the people_list list to an empty list: if people_list == []

You can play around with the code by adding elements to the list to see which if...else statement gets executed.

Summary

In this article, we saw how to check if a list is empty in Python by using three different methods.

We saw how to check if a list is empty by using the not operator, and the len() function.

We also saw how check if a list is empty by comparing it to an empty list.

Happy coding!