How to Fix IndexError - List Index Out of Range in Python Last Updated : 19 Nov, 2024 Comments Improve Suggest changes Like Article Like Report IndexError: list index out of range is a common error in Python when working with lists. This error happens when we try to access an index that does not exist in the list. This article will explore the causes of this error, how to fix it and best practices for avoiding it.Example: Python a = [1, 2, 3] print(a[3]) # IndexError ERROR!Traceback (most recent call last): File "", line 2, in IndexError: list index out of rangeTable of ContentCauses of IndexError: List Index Out of RangeAccessing an index that exceeds the length of the listAccessing a negative index that doesn’t existIterating over a list incorrectly using loopsHow to Fix IndexErrorCheck the List Length Before AccessingUse Negative Indexes CorrectlyIterate Safely in LoopsUse Enumerate for Safe IterationUse Try-Except to Handle ErrorsCauses of IndexError: List Index Out of RangeThis error usually occurs under the following conditions:1. Accessing an index that exceeds the length of the list Python a = [1, 2, 3] print(a[5]) # IndexError 2. Accessing a negative index that doesn’t exist Python a = [1, 2, 3] print(a[-4]) # IndexError 3. Iterating over a list incorrectly using loops Python a = [1, 2, 3] for i in range(len(a) + 1): # Incorrect range # IndexError when i = 3 print(a[i]) How to Fix IndexErrorHere’s how we can resolve and avoid this error with examples:1. Check the List Length Before AccessingAlways verify the length of the list before accessing an index. Python a = [10, 20, 30] # Let suppose we want to access 'idx' index idx = 2 if len(a) > idx: print(a[idx]) # Safe access else: print("Index out of range") Output30 2. Use Negative Indexes CorrectlyNegative indexes start from the end of the list. So, make sure that index don’t exceed the list boundaries. Python a = [10, 20, 30] try: # Valid negative index print(a[-1]) # Invalid negative index print(a[-4]) except IndexError: print("Negative index is out of range.") Output30 Negative index is out of range. 3. Iterate Safely in LoopsWhen iterating over a list make sure that index don’t exceed the list boundaries. Python a = [10, 20, 30] for i in range(len(a)): print(a[i]) Output10 20 30 4. Use Enumerate for Safe IterationEnumerate provides the index and value of a list and this index will never go out of bounds. Python a = [10, 20, 30] for idx, val in enumerate(a): print(f"Index: {idx}, Value: {val}") OutputIndex: 0, Value: 10 Index: 1, Value: 20 Index: 2, Value: 30 5. Use Try-Except to Handle ErrorsUsing a try-except block we can prevent our program to crash and allows us to handle errors easily. Python a = [10, 20, 30] # Let suppose we want to access 'idx' index idx = 3 try: print(a[idx]) except IndexError: print("Index is out of range. Please check your list.") OutputIndex is out of range. Please check your list. Comment More infoAdvertise with us Next Article How to Fix IndexError - List Index Out of Range in Python S shikher09 Follow Improve Article Tags : Python python-list Python How-to-fix Practice Tags : pythonpython-list Similar Reads Python Indexerror: list assignment index out of range Solution In Python, the IndexError: list assignment index out of range occurs when we try to assign a value to an index that exceeds the current bounds of the list. Since lists are dynamically sized and zero-indexed, it's important to ensure the index exists within the list's range before modifying it. Under 2 min read Python List index() - Find Index of Item index() method in Python is a helpful tool when you want to find the position of a specific item in a list. It works by searching through the list from the beginning and returning the index (position) of the first occurrence of the element you're looking for. 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