[Python-3000] optimizing [x]range (original) (raw)

skip at pobox.com skip at pobox.com
Mon Jul 30 04:17:24 CEST 2007 

Greg> I think the use cases for this are where you're trying to express
Greg> a range-like condition, i.e 'a <= x < b'. Then you have to make
Greg> sure you get the right relations in the right places, which is the
Greg> same kind of burden as remembering to add or subtract 1 in the
Greg> right places.

I think it's easier to learn that 'a <= x < b' is logically equivalent to 'a <= x and x < b' than inferring that 'x in range(a, b)' means the same thing. In fact, due to shortcut semantics they actually don't mean quite the same thing since b might not get evaluated in the cascading comparison case. Given that I find the cascading comparisons clearer I see no reason to optimize the "in range(...)" case.

Skip

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