range

[Bjorn Pettersen]

> From: Hilbert [mailto:hilbert at microsoft.com] 
> 
> Why does range(1,4,1) return [1,2,3]?
> It does not make sense at all.
> It should return [1,2,3,4].
> 
> Am I crazy?

Perhaps <wink>.

range(n) returns the exact indices for which a sequence s with len(s) ==
n are valid, so:

  for i in range(len(s)):
      ...

iterates over all elements, while with your version it would have been:

  for i in range(len(s)-1):
      ...

a probably frequent cause for off-by-one errors.

practicality-beats-purity'ly y'rs
-- bjorn

ps: there's a longer rationale based on half-open intervals that you can
probably find on google.