efficiency of range() and xrange() in for loops

[Giovanni Bajo]

Steve R. Hastings wrote:

>> in Python 2.X, range is defined to return a list.  if you start
>> returning something else, you'll break stuff.
>
> Perhaps I'm mistaken here, but I don't see how this optimization could
> possibly break anything.

Because you assume that the only use-case of range() is within a for-loop.
range() is a builtin function that can be used in any Python expression. For
instance:

RED, GREEN, BLUE, WHITE, BLACK = range(5)
-- 
Giovanni Bajo