What does the list index out of range mean?

What does the list index out of range mean?

This means the index that you are using for an array is going beyond the array limit.

For example, let’s say you have declared an array of size 10 and they doing array [20]. This will cause an index out of range issue.

This is perhaps the most common errors faced by programmers regardless of the language you write.

It means you are trying to access an element in an array or list, but you are pointing outside that array.

Best way to handle the error is to watch/print/echo the counter variable prior to the use of the arrays.

Check the counter value, it will most likely be one value higher than the array size.

This simply means that you are requesting an element of a list with an index that does not exist in a list.

For example, if you have a list:

alist = [1,2,3,4] then for print(alist[0]) you will get number 1, while for print(alist[3]) you will get 4 and for print(alist[6]) you will get an error with message list index out of range, because the list has indexes up to 3, and it starts with index 0.

I hope this clears it up.

I found this quite useful video on youtube if you want to learn more about lists:

What does the list index out of range mean?

When we access elements in a list using index and index is greater and equal to list length then index out of range errors occur.


List1=[1, 2,3,4]

Indexes are the 0,1,2,3 (<length of list)

Length of the list is 4

If we access elements in the list whose index greater than 3 then it will show an error



Here index is 4 which is equal to the length of the list so we can’t access it

A “list index out of range” error is given now in the 2nd case because the element being accessed – the 7th element – does not exist in the list and hence exceeds its range.

Hence, you should only access elements that fall within the range of the elements of the list which would be max up to 5 as a total of 6 elements exist.

check out the following code in python

  • >>> even = [ 2, 4, 6, 8 ]
  • >>> even[1]
  • 4
  • >>> even[3]
  • 8
  • >>> even[5]
  • Traceback (most recent call last):
  • File “<pyshell#7>”, line 1, in <module>
  • even[5]
  • IndexError: list index out of range

So in the above code, we have defined even lists that contain 4 elements with starting index 0 and last index 3.

clearly this means you can’t access any elements in even list if you go beyond your last index value.

And if u try, then u will get a list index out of range error.

In python list is mutable, so the size is not fixed.

Due to size is not fixed, the available index is greater than the assigned index for a list(available index > assigned index).

If you try to access the empty or None element by pointing available index of the list, Then you will get the list index out of range error.

open python and dirty your hands with this below code, to have a better understanding.

>>x = list(‘1234’)
> x
[‘1’ , ‘2’ , ‘3’, ‘4’]
>>length = len(x)
>> x[length]
Index Error: list index out of range

NOTE: The list index starts from zero(0). But here the length is four.

The assignment of above list is like:

  • x[0] = 1
  • x[1] = 2
  • x[2] = 3
  • x[3] = 4
  • x[4] = ?

If you try to access the x[4] which is None or Empty, the list index out of range will come.

list index out of range mean

What does the error: “IndexError: list index out of range” imply in the following piece of code?

In Python, Lists are one of the important topics they are mutable(Can be changed dynamically)

Index Error is a common error, which occurs when a user wants to find a List object which is not found in the declared list, In the below example there are only 6 list objects from 0–5, if we want to find a list object at index 6 we gonna get an error.

It might be these two cases.

  1. index’s value which you’re getting must have been out of the range – (zero, len(index-1)).
  2. If you haven’t bounded a list object to the exposed name which is pointing at it. Basically this means, you haven’t defined the exposed list object. In that case without assigning any element before, if you try to assign the first element it gives an error. So you should append it first.

To debug any code, just print index value each time if it is in a loop and observe. If not you have got the best checker i.e. “Python Shell”.

List Index out of range basically means you are trying to access a value at an index which is out of bounds i.e greater than the last index of the list or less than the last index in the list i.e 0

If you are looking for how to debug list index out of range error, then the simple idea would be to print out the list indices along with the length of the list and see what might be causing the error to begin with.

Consider a list of integers:

a= range(5)


It has indices from 0,1,2,3,4.

For example:

If you try:

a[0] , a[1], a[4] , a[-2]

[OUT]: 0 1 4 3

When you try to access the index of the list of ‘a’ which is not from the above indices. You get an IndexError.


[Out]: IndexError

Since you’re trying to access an index ‘5’ which is not assigned to any of the elements in the list ‘a’.

Another case:

Where you’re trying to access some index from an empty list:



Even in this case, it holds the very same reason since your trying to access the index which is out of the scope.

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What does the error: “IndexError: list index out of range” imply in the following piece of code?

Nancy Ajram

I am Nancy Ajram from Dubai, the beauty queen of UAE.

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