2. How would the initial value that forms the basis of summation be built for non-empty sequences?
Here's you're way off. There's never any use of "+=", so never any need to create a new object. The algorithm I had in mind was:
- if empty, return 2nd arg
- if one item, return that
- if more than one item (A, B, C, ...) return (...((A + B) + C) + ...)
There I go again, missing the obvious and thinking things are more complicated than they really are. . .
But I'm not so sure now. Thinking ahead to generic types, I'd like the full signature to be:
def sum(seq: sequence[T], initial: T = 0) -> T.
and that's exactly what it is today. Conclusion: sum() is perfect after all!
So the official verdict is "sum() is mainly intended for numbers, but can be used with other types by supplying a default argument"?
I guess that leaves Alex's question of whether or not supplying a string of some description as the initial value can be legitimately translated to:
if isinstance(initial, basestring):
return initial + type(initial)().join(seq)rather than raising the current TypeError that suggests the programmer may want to rewrite their code.
Cheers, Nick.
--
Nick Coghlan | [EMAIL PROTECTED] | Brisbane, Australia
---------------------------------------------------------------
http://boredomandlaziness.skystorm.net
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