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
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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 you’re 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])
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
"list index out of range"
I’m following this tutorial and I’ve double and triple checked that I have it as the author wrote it, but I get a “list index out of range” error when I try to run it. The line 15- super().init(pos, self.frames[self.frame_index], groups, z) is where it stops in the debug. More on forum.freecodecamp.org
5
0
August 28, 2024IndexError: list index out of range even though its not
Not that I want to pull you apart, but if the code is quite messy, then it’s going to be difficult for you to debug, let alone someone else · Try this (assuming that line 35 is still if(player[4] < monster[3]):)… At line 34 introduce print(player, monster) so that you can see what’s ... More on discuss.python.org
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0
March 29, 2023Beginner level - Getting an error "IndexError: list index out of range" in a tutorial program
Hello, I am learning a coding language for the first time and that is Python. During my attempt to solve an online coding exercise I got a partially successful output - I got the results correct, but I also got an error message that I want to avoid. Pl. see the attached pic.: Can you pl. explain ... More on discuss.python.org
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0
November 13, 2022Videos
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Rollbar
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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
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 iterating through a list and trying to access an item that doesn't exist. One common instance where this can occur is when you use the wrong integer in Python's range() function.
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.
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.
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 - Must be 0-{len(items)-1}") # Or use modulo for wrapping item = items[user_index % len(items)] # Problem: Lists have different lengths names = ["Alice", "Bob"] ages = [25, 30, 35] for i in range(len(ages)): print(f"{names[i]} is {ages[i]}") # IndexError when i=2 # Solution 1: Use zip (stops at shortest) for name, age in zip(names, ages): print(f"{name} is {age}") # Solution 2: Check both lengths min_len = min(len(names), len(ages)) for i in range(min_len): print(f"{names[i]} is {ages[i]}") # Solution 3: Use zip_longest with default from itertools import zip_longest for name, age in zip_longest(names, ages, fillvalue="Unknown"): print(f"{name} is {age}")
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?
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.
freeCodeCamp
forum.freecodecamp.org › programming
"list index out of range" - Programming - The freeCodeCamp Forum
August 28, 2024 - I’m following this tutorial and I’ve double and triple checked that I have it as the author wrote it, but I get a “list index out of range” error when I try to run it. The line 15- super().init(pos, self.frames[self.frame_index], groups, z) is where it stops in the debug.
GeeksforGeeks
geeksforgeeks.org › python › python-indexerror-list-assignment-index-out-of-range-solution
Python Indexerror: list assignment index out of range Solution - GeeksforGeeks
July 23, 2025 - 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 ...
freeCodeCamp
freecodecamp.org › news › list-index-out-of-range-python-error-solved
List Index Out of Range – Python Error [Solved]
August 3, 2022 - The easy fix is to always use an index that exists in a list when trying to access items in the list. Loops work with conditions. So, until a certain condition is met, they'll keep running.
LearnDataSci
learndatasci.com › solutions › python-indexerror-list-index-out-range-and-python
IndexError: list index out of range and python – LearnDataSci
The addition of if color != 'blue' ... finished iterating through all of the list values, we replace the old list. This index error is triggered when indexing a list using a value outside of its range ......
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.
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 - An index in Python refers to a position within an ordered list . 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.
Python.org
discuss.python.org › python help
IndexError: list index out of range even though its not - Python Help - Discussions on Python.org
March 29, 2023 - Not that I want to pull you apart, but if the code is quite messy, then it’s going to be difficult for you to debug, let alone someone else · Try this (assuming that line 35 is still if(player[4] < monster[3]):)… At line 34 introduce print(player, monster) so that you can see what’s ...
Top answer 1 of 3
1
Please do not post code in screenshots. Paste the actual code using proper formatting instead.
Your loop condition is while i <= len(List1), meaning the loop will run if i is exactly equal to len(List1). Consider the case were List1 contains only one element, i.e. its length is 1. Will List1[1] wor…
2 of 3
0
Wow, lovely. Thanks for a quick and accurate help. I corrected line 4 in the code and it worked:
string = str(input(“Input your string”))
List1 = list(string)
i=0
while i
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 - You should now know what the index out of range error in Python means, why it pops up, and how to prevent it in your Python programs. A useful way to debug this error and understand how your programs are running is simply to print the index and compare it to the length of your list.
Medium
medium.com › @python-javascript-php-html-css › python-list-index-out-of-range-recognizing-the-problem-even-when-indexes-are-checked-a0cd7d7a0680
Python List Index Out of Range: Recognizing the Problem Even When Indexes Are Checked
November 14, 2024 - The scripts provided address a common Python issue: handling “list index out of range” errors that can arise even when the indexes appear correct. One function, get_second_largest, aims to find the second-largest number in a list. At first glance, this is straightforward, but an issue occurs when removing elements inside a loop.
Rollbar
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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