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How to Solve "IndexError: pop from empty list" in Python

The IndexError: pop from empty list error in Python is straightforward: you're trying to use the pop() method on a list that has no elements.

This guide explains the cause and, more importantly, how to prevent this error with simple, robust checks.

Why the Error Occurs​

The list.pop() method removes and returns an item from a list. By default, it removes the last item:

my_list = ['tutorial', 'reference', 'com']
last_item = my_list.pop()
print(last_item)  # Output: com
print(my_list)   # Output: ['tutorial', 'reference']

You can also specify an index to remove a specific item:

my_list = ['tutorial', 'reference', 'com']
second_item = my_list.pop(1) # Remove element at index 1
print(second_item) # Output: reference

However, if the list is empty, there's nothing to remove, and pop() raises the IndexError:

my_list = []

# ⛔️ IndexError: pop from empty list
# result = my_list.pop()  # This causes the error

The most Pythonic and efficient way to prevent this error is to check if the list is empty before calling pop(). Empty lists are "falsy" in Python, so a simple if statement works:

my_list = []

if my_list:  # Checks if the list is NOT empty
    result = my_list.pop()
    print(result)
else:
    print('The list is empty')  # Output: The list is empty
  • if my_list:: This is the key. This condition is True if my_list has at least one element, and False if it's empty. This is the best and most concise way to check for an empty list.

Preventing IndexError with len(my_list)​

You can also explicitly check the length of the list:

my_list = []

if len(my_list) > 0:  # or, equivalently: if len(my_list):
    result = my_list.pop()
    print(result)
else:
    print('The list is empty') # Output: The list is empty
  • len(my_list) > 0: This explicitly checks if the list has any elements. It's functionally equivalent to if my_list:, but less concise.

Using try-except (Generally Avoid for This Specific Case)​

While you can use a try-except block to catch the IndexError, it's generally not recommended for this specific problem. The if check is simpler and more readable. try-except is better suited for handling unexpected errors, not predictable situations like an empty list.

my_list = []

try:
    result = my_list.pop()
    print(result)
except IndexError:
    print('The list is empty')  # Output: The list is empty

If you do use try-except, and you don't need to do anything specific in the except block, use pass:

my_list = []

try:
    result = my_list.pop()
    print(result)
except IndexError:
    pass # We handled it, just do nothing else

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