How To Check If List Is Null Python

In this tutorial, we will learn how to check if a given list is null in Python. A list is considered null or empty when it has no elements. Before performing any operations on a list, it’s a good practice to check if it’s null or not. This can help avoid bugs and unexpected errors in your code.

Step 1: Create a Python list

First, let’s create a list in Python:

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my_list = []

This list is empty or null since it has no elements.

Step 2: Using the len() function

One way to check if a list is null is by using the built-in len() function, which returns the number of elements in a list. If the length of a list is 0, it means the list is null. Here’s an example:

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if len(my_list) == 0:
    print("The list is null")
else:
    print("The list is not null")

The output will be:

The list is null

Step 3: Using the not operator

An alternative approach is using the not operator, which returns True if the list is empty and False otherwise:

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if not my_list:
    print("The list is null")
else:
    print("The list is not null")

This approach is more concise than using the len() function. The output will be the same as before:

The list is null

The full code:

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my_list = []
 
# Using the len() function
if len(my_list) == 0:
    print("The list is null")
else:
    print("The list is not null")
 
# Using the not operator
if not my_list:
    print("The list is null")
else:
    print("The list is not null")

Conclusion

In this tutorial, we learned two ways to check if a list is null or empty in Python. You can choose the one that suits your coding style and requirements. Keep in mind that checking for empty lists is a good practice, as it helps prevent errors and bugs in your code.