IndexError: pop from Empty List in Python

The IndexError: pop from an empty list is a common issue in Python, occurring when an attempt is made to use the pop() method on a list that has no elements. This article explores the nature of this error, provides a clear example of its occurrence, and offers three practical solutions to handle it effectively. Here, we will see how to fix Pop From Empty List’ Error in Python.

What is IndexError: pop from empty list Error in Python?

IndexError: Pop From Empty List’ Error in Python error occurs when the pop() method is applied to an empty list, where the operation of removing and returning the last element is invalid due to the absence of elements. This leads to a runtime error, specifically an IndexError.

Why does Pop From Empty List Error Occurs?

Below are some of the scenarios when this error occurs:

• Empty List Pop Attempt
• Looping Through an Empty List

Popping Empty List in Python

In this scenario, attempting to pop an element using pop() from an empty list leads to the ‘Pop From Empty List’ error.

Python3

my_list = []
popped = my_list.pop()

Output:

Hangup (SIGHUP)
Traceback (most recent call last):
  File "Solution.py", line 2, in <module>
    popped_element = my_list.pop()
IndexError: pop from empty list

Looping Through an Empty List

When iterating over an empty list and attempting to pop elements inside a loop, the ‘Pop From Empty List’ error is triggered.

Python3

my_list = []
for i in range(len(my_list)+1):
    popped = my_list.pop()

Output:

Hangup (SIGHUP)
Traceback (most recent call last):
  File "Solution.py", line 3, in <module>
    popped_element = my_list.pop()
IndexError: pop from empty list

Fix the ‘Pop From Empty List’ Error

Below are some of the ways by which we can prevent the ‘Pop From Empty List’ Error in Python:

• Checking if the List is Truthy Before Calling pop()
• Checking for the List’s Length Before Calling pop()
• Using a Try/Except Statement to Handle the Error

Checking if the List is Truthy Before Calling pop()

In this example, we check if the list my_list is truthy before attempting to use the pop() method. If the list is not empty, the last element is popped and printed; otherwise, a message is displayed indicating an empty list.

Python3

mylist = []

if mylist:
    res = mylist.pop()
    print(res)
else:
    print('The list is empty')

Output

The list is empty

Checking for the List’s Length Before Calling pop()

Here, we explicitly check if the length of my_list is greater than 0 before calling pop(). If the list has elements, the last one is popped and printed; otherwise, a message is shown for an empty list.

Python3

mylist = []

if len(mylist) > 0:
    res = mylist.pop()
    print(res)
else:
    print('The list is empty')

Output

The list is empty

Using a Try-Except Statement to Handle the Error

In this example, we use a try/except block to attempt pop() on my_list. If an IndexError occurs (indicating an attempt to pop from an empty list), it is caught, and a message is printed to handle the case of an empty list gracefully.

Python3

mylist = []

try:
    res = mylist.pop()
    print(res)
except IndexError:
    print('The list is empty')

Output

The list is empty