Fredrik Lundh wrote: > Dustan wrote: > > > It's always nice to know there are such good-natured people ready to > > help on this group. > > any special reason why you keep pretending that some random wikipedia > editor knows more about a future Python release than the people that > develops Python ?
Be careful how you word that - this is the first time I've ever referenced wikipedia in a question on this forum. > > Anyway, I figured out a way to get the builtin > > function 'sum' to work as I need: > > sum([[1,2,3],[4,5,6],[7,8,9]], []) > > sum() is designed for adding numbers, not sequences. abusing it > for sequences leads to inefficient code, and extremely bad worst- > case behaviour, since you end up copying the same data over and > over and over again Thanks for some quality feedback for a change. Why can't you do that more often? > -- the function even checks for strings for > this very reason: > > >>> sum(["123", "456", "789"], "") > Traceback (most recent call last): > File "<stdin>", line 1, in ? > TypeError: sum() can't sum strings [use ''.join(seq) instead] > > (maybe it should check for other well-known containers as well?) > > if you care about writing robust code, why not just use a for-loop, > and the list extend method? Because I'm embedding this expression in a list comprehension (as I stated in my original post), and last time I checked, it's not possible to treat a for-loop as an expression (which is what a list comprehension requires). > </F> -- http://mail.python.org/mailman/listinfo/python-list
