How to check if list is empty in python

PythonHow-ToBeginner · 3 min read

How to Check if a List is Empty in Python: Simple Guide

To check if a list is empty in Python, use the condition if not my_list: which returns True if the list has no items. Alternatively, you can check the length with if len(my_list) == 0:.

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Syntax

There are two common ways to check if a list is empty in Python:

if not my_list: - This checks if the list is empty by evaluating its truthiness.
if len(my_list) == 0: - This explicitly checks if the list length is zero.

Both methods return True when the list has no elements.

python

if not my_list:
    print("List is empty")

if len(my_list) == 0:
    print("List is empty")

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Example

This example shows how to check if a list is empty using both methods and prints a message accordingly.

python

my_list = []

if not my_list:
    print("The list is empty using 'if not my_list'")

if len(my_list) == 0:
    print("The list is empty using 'len(my_list) == 0'")

Output

The list is empty using 'if not my_list' The list is empty using 'len(my_list) == 0'

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Common Pitfalls

Some beginners try to compare the list directly to an empty list like if my_list == []:. While this works, it is less efficient and less Pythonic than using if not my_list:. Also, avoid checking if my_list is None: because an empty list is not None.

python

my_list = []

# Less efficient way
if my_list == []:
    print("List is empty (less efficient way)")

# Recommended way
if not my_list:
    print("List is empty (recommended way)")

Output

List is empty (less efficient way) List is empty (recommended way)

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Quick Reference

Method	Description	Example
Using truthiness	Checks if list is empty by evaluating its truth value	if not my_list:
Using length	Checks if list length is zero	if len(my_list) == 0:
Comparing to empty list	Directly compares list to [] (less efficient)	if my_list == []:

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Key Takeaways

Use 'if not my_list:' to check if a list is empty in the most Pythonic way.

Checking 'len(my_list) == 0' also works but is more verbose.

Avoid comparing the list directly to [] for efficiency and style reasons.

An empty list is not the same as None; do not confuse these checks.