IndexError: list index out of range

Understanding IndexError: List Index Out of Range

Introduction:

The “IndexError: list index out of range” message occurs when you attempt to access an element in a list using an index that doesn’t exist. This can happen if the index is too high, equal to the list’s length, or if a negative index exceeds the list’s bounds. Understanding this error is key to effective debugging. Let’s look at common causes and solutions.

Common Causes and Solutions for IndexError

The Problem:

This error happens when you try to access an index in a list that doesn’t exist. For example:

my_list = [1, 2, 3]
print(my_list[3])
# IndexError: list index out of range

In this case, the highest index in my_list is 2, so attempting to access index 3 throws an error.

The Solution:

To avoid this, check the length of the list before accessing an index:

my_list = [1, 2, 3]
if len(my_list) > 3:
print(my_list[3])
else:
print(“Index out of range”) # Output: Index out of range