[Python-Dev] Rationale for sum()'s design?

Nick Coghlan ncoghlan at iinet.net.au
Thu Mar 17 15:54:02 CET 2005

Guido van Rossum wrote:
>>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)
> If you're trying to get people in the habit of writing sum(x, "")
> instead of "".join(x), I fear that they'll try sum(x, " ") instead of
> " ".join(x), and be sadly disappointed.

That works for me as a reason not to provide this feature.

It's somewhat heartening when discussions like this turn out to show that the 
original design was right after all :)


Nick Coghlan   |   ncoghlan at email.com   |   Brisbane, Australia

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