Does “IndexError: list index out of range” when trying to access the N’th item mean that my list has less than N items?

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?

Answers:

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Method 1

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:

IndexError

The IndexError is raised when you attempt to retrieve an index from a sequence, like a list or a tuple, 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 IndexError doesn’t give you great information. You can see that you have a sequence reference that is out of range and what the type of the sequence is, a list in this case. That information, combined with the rest of the traceback, is usually enough to help you quickly identify how to fix the issue.

Method 2

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?

Method 3

The way Python indexing works is that it starts at 0, so the first number of your list would be [0]. You would have to print[52], as the starting index is 0 and
therefore line 53 is [52].

Subtract 1 from the value and you should be fine. 🙂

Method 4

Yes. The sequence doesn’t have the 54th item.

Method 5

That’s right. ‘list index out of range’ most likely means you are referring to n-th element of the list, while the length of the list is smaller than n.

Method 6

Always keep in mind when you want to overcome this error, the default value of indexing and range starts from 0, so if total items is 100 then l[99] and range(99) will give you access up to the last element.

whenever you get this type of error please cross check with items that comes between/middle in range, and insure that their index is not last if you get output then you have made perfect error that mentioned above.

Method 7

If you read a list from text file, you may get the last empty line as a list element.
You can get rid of it like this:

list.pop()
for i in list:
   i[12]=....

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