"jfj" wrote: > Why can't we __setitem__ for tuples?
http://www.python.org/doc/faq/general.html#why-are-there-separate-tuple-and-list-data-types > The way I see it is that if we enable __setitem__ for tuples there > doesn't seem to be any performance penalty if the users don't use it > (aka, python performance independent of tuple mutability). how would you implement a dictionary where the keys could change, without any performance penalty compared to the current implementation? > On the other hand, right now we have to use a list if we want to > __setitem__ on a sequence. If we could use tuples in the cases where > we want to modify items but not modify the length of the sequence, > programs could be considerably faster. really? in what way are tuples faster than lists? have you noticed that "a[i]" is actually faster if "a" is a list? (especially in 2.2 and earlier). </F> -- http://mail.python.org/mailman/listinfo/python-list