Generally it means that you are providing an index for which a list element does not exist.
E.g, if your list was [1, 3, 5, 7], and you asked for the element at index 10, you would be well out of bounds and receive an error, as only elements 0 through 3 exist.
Reddit
reddit.com › r/learnpython › "indexerror: list index out of range" not sure how to fix
r/learnpython on Reddit: "IndexError: list index out of range" not sure how to fix
January 4, 2023 -
I'm wondering how to format my "for loop" so it applies to any list of numbers inputted and so I don't get this error: "IndexError: list index out of range" and also .
I'm having a hard time understanding when to use what in my loops (i.e. for x in range(value) vs for x in value), or when to use while loops, etc. Are there any detailed guides on this somewhere? i have 3 books and I've searched the internet, but haven't found anything that's both understandable and goes into greater detail.
Here is my code, it calculates what I want (New = 2, 3), but I get the error at the end and I'm not sure how to fix it.
values = [2, 2, 3, 3, 3]
numbers = values.copy()
for x in range(len(numbers)):
while numbers[x] == numbers[x-1]:
del numbers[x]
print(f"Original = {values}")
print(f"New = {numbers}")
This is the output for my code:
Original = [2, 2, 3, 3, 3]
New = [2, 3, 3, 3]
Original = [2, 2, 3, 3, 3]
New = [2, 3, 3]
Original = [2, 2, 3, 3, 3]
New = [2, 3]
Traceback (most recent call last):
while numbers[x] == numbers[x-1]:
IndexError: list index out of range Top answer 1 of 4
3
I believe it is because you are deleting a value in your array while youre in the middle of iterating through it. If you’re looping through with an original length of 5 and you delete one the new length is now 4 but you are still attempting to loop over the original 5 which is why you’re getting an index error. It looks like you are trying to remove duplicates from an array. The better way to do this would be to add each element to a new array only if it is not already in the new array. An even better way would be to use a set.
2 of 4
2
Once again... removing items from a list while you iterate over its length is a nono. As you remove items the list is getting shorter, at one point the index x will be higher than actual length of the list. Just a minute ago I was answering a similar question! Create a new list with only the items you want instead of removing item from a list. Also in your case that while serves nothing. newlist = values[0] for x in range(1, len(values)): if values[x] != values[x-1]: newlist.append(values[x])
Having Issues with error, can someone explain why I am getting an IndexError: list index out of range? Mar 9, 2021
r/learnpython 5y ago
python - Does "IndexError: list index out of range" when trying to access the N'th item mean that my list has less than N items? - Stack Overflow
I'm telling my program to print out line 53 of an output. Is this error telling me that there aren't that many lines and therefore can not print it out? More on stackoverflow.com
Newbie Issue: "IndexError: list index out of range"
The place variable is set to 0 before the first iteration of the while loop, and inside the for loop it is increased by one for every element in nene, do you see why? Then, on the next go through the while loop, the place variable is not reset, and is already larger than the length of the nene array, so doing nene[place][0] will give you an index error. More on reddit.com
4
1
May 5, 2020'List index out of range' when it is not.
learn how to use a debugger and see what that list looks like at that particular line of code More on reddit.com
22
1
March 27, 2021list index out of range. i need help !
without going too deep into reading all your code, the issue is with your get_cages function. you try B.get_cages()[0] which suggests get_cages() is returning an empty list, or there is some other issue. Before the line out=…., do a print(B.get_cages()) to see if there is anything in the list. More on reddit.com
4
0
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Codecademy
codecademy.com › forum_questions › 524e0750f10c60448f001750
What does the error 'list index out of range' mean? | Codecademy
Generally, list index out of range means means that you are providing an index for which a list element does not exist.
freeCodeCamp
freecodecamp.org › news › list-index-out-of-range-python-error-message-solved
List Index Out of Range – Python Error Message Solved
January 20, 2022 - You'll get the Indexerror: list index out of range error when you try and access an item using a value that is out of the index range of the list and does not exist.
Rollbar
rollbar.com › home › how to fix indexerror: list index out of range in python
How to Fix "IndexError: list index out of range" in Python
The IndexError: list index out of range almost always comes down to one thing: your code assumes the list has more elements than it actually does. The fix is to make sure you're never reaching past the end.
Published February 15, 2026
OneUptime
oneuptime.com › home › blog › how to fix 'indexerror: list index out of range' in python
How to Fix 'IndexError: list index out of range' in Python
January 25, 2026 - The IndexError: list index out of range occurs when you try to access a list element using an index that does not exist.
GeeksforGeeks
geeksforgeeks.org › python › python-list-index-out-of-range-indexerror
How to Fix IndexError - List Index Out of Range in Python - GeeksforGeeks
2 weeks ago - IndexError: list index out of range, occurs when we try to access a list element using an index that does not exist.
LearnDataSci
learndatasci.com › solutions › python-indexerror-list-index-out-range-and-python
IndexError: list index out of range and python – LearnDataSci
This index error is triggered when indexing a list using a value outside of its range of indexes. The best way to avoid it is by carefully considering what range of indexes a list might have, taking into account that list indexes start at zero instead of one.
Opensource.com
opensource.com › article › 23 › 1 › fix-indexerror-python
How to fix an IndexError in Python | Opensource.com
January 19, 2023 - The only solution to fix the IndexError: list index out of range error is to ensure that the item you access from a list is within the range of the list.
Rollbar
rollbar.com › home › how to fix python’s “list index out of range” error in for loops
Fix Python List Index Out of Range Error | Rollbar
Fix Python's list index out of range error in for loops with enumerate(), length checks, or -1 to safely access the last item.
Published March 25, 2025
LearnPython.com
learnpython.com › blog › list-index-out-of-range
How to Fix the “List index out of range” Error in Python | LearnPython.com
June 26, 2023 - The short answer is: this error occurs when you’re trying to access an item outside of your list’s range. The long answer, on the other hand, is much more interesting. To get there, we’ll learn a lot about how lists work, how to index things the bad way and the good way, and finally how to solve the above-mentioned error.
Career Karma
careerkarma.com › blog › python › python indexerror: list index out of range solution
Python indexerror: list index out of range Solution | Career Karma
December 1, 2023 - If you are using a loop to access an item, make sure that loop accounts for the fact that lists are indexed from zero. If that does not solve the problem, check to make sure that you are using range() to access each item by its index value. Now you’re ready to solve the “indexerror: list index out of range” error like a Python expert!
freeCodeCamp
freecodecamp.org › news › list-index-out-of-range-python-error-solved
List Index Out of Range – Python Error [Solved]
August 3, 2022 - If you try to access an item in a list using an index that is out of range, you'll get the IndexError: list index out of range error.
Flexiple
flexiple.com › python › list-index-out-of-range-python
List Index Out of Range – Python Error [Solved] - Flexiple - Flexiple
March 10, 2022 - You get the list index out of range Python error because your code attempts to access an index in a list that does not exist. List index out of range error typically occurs in two common scenarios: Exceeding List Boundaries: Python lists are ...
airbrake
docs.airbrake.io › home › blog › python › python index error: index out of range
Python Index Error: Index Out of Range - Airbrake Docs
November 23, 2021 - Python supports the indexing of list elements. This helps access iterable items and perform operations on them, such as printing or looping through elements. But, if you mention an index in your code that is outside the range of the list, Python will throw an IndexError telling you that the list index is out of range.
MakeUseOf
makeuseof.com › home › programming › what does the python "list index out of range" error mean?
What Does the Python "List index out of range" Error Mean?
March 11, 2022 - When Python throws a "list index out of range" error, it means you tried to slice the list beyond its last index.
Esri Community
community.esri.com › t5 › data-management-questions › indexerror-list-index-out-of-range › td-p › 283369
Solved: IndexError: list index out of range - Esri Community
November 8, 2021 - This error basically means you are trying to access a value at a List index which is out of bounds i.e greater than the last index of the list or less than the least index in the list. So the first element is 0, second is 1, so on. So if there are n elements in a list, the last element is n-1 ...
Top answer 1 of 7
94
If you have a list with 53 items, the last one is thelist[52] because indexing starts at 0.
From Real Python: Understanding the Python Traceback - IndexError:
IndexErrorThe
IndexErroris raised when you attempt to retrieve an index from a sequence, like alistor atuple, and the index isn’t found in the sequence. The Python documentation defines when this exception is raised:Raised when a sequence subscript is out of range. (Source)
Here’s an example that raises the
IndexError:
test = list(range(53))
test[53]
---------------------------------------------------------------------------
IndexError Traceback (most recent call last)
<ipython-input-6-7879607f7f36> in <module>
1 test = list(range(53))
----> 2 test[53]
IndexError: list index out of range
The error message line for an
IndexErrordoesn’t give you great information. You can see that you have a sequence reference that isout of rangeand what the type of the sequence is, alistin this case. That information, combined with the rest of the traceback, is usually enough to help you quickly identify how to fix the issue.
2 of 7
37
Yes,
You are trying to access an element of the list that does not exist.
MyList = ["item1", "item2"]
print MyList[0] # Will work
print MyList[1] # Will Work
print MyList[2] # Will crash.
Have you got an off-by-one error?
Rollbar
rollbar.com › home › how to fix “indexerror: list assignment index out of range” in python
Fix IndexError: List Index Out of Range in Python | Rollbar
The IndexError: List Assignment Index Out of Range error occurs when you assign a value to an index that is beyond the valid range of indices in the list.
Published September 6, 2023
LabEx
labex.io › tutorials › python-how-to-fix-indexerror-list-index-out-of-range-417491
How to fix IndexError: list index out of range | LabEx
The IndexError: list index out of range exception is a common error that occurs when you try to access an element in a list using an index that is outside the valid range of the list.