Fix Python – Why does range(start, end) not include end?

Question

Asked By – MetaGuru

>>> range(1,11)

gives you

[1,2,3,4,5,6,7,8,9,10]

Why not 1-11?

Did they just decide to do it like that at random or does it have some value I am not seeing?

Now we will see solution for issue: Why does range(start, end) not include end?


Answer

Because it’s more common to call range(0, 10) which returns [0,1,2,3,4,5,6,7,8,9] which contains 10 elements which equals len(range(0, 10)). Remember that programmers prefer 0-based indexing.

Also, consider the following common code snippet:

for i in range(len(li)):
    pass

Could you see that if range() went up to exactly len(li) that this would be problematic? The programmer would need to explicitly subtract 1. This also follows the common trend of programmers preferring for(int i = 0; i < 10; i++) over for(int i = 0; i <= 9; i++).

If you are calling range with a start of 1 frequently, you might want to define your own function:

>>> def range1(start, end):
...     return range(start, end+1)
...
>>> range1(1, 10)
[1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

This question is answered By – moinudin

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