On Tuesday 27 October 2009 07:29:46 am Steve wrote:
> To me the current implementation is blatantly correct. sum is an
> operation on a list of numeric values, returning a numeric value -
> this is why we have the seemingly strange "".join() rather than [].join
> ("")But then, why does sum() accept non-numeric input? How does sum decides if the arguments are "numbers", given that it accepts almost everything that defines __add__ (except strings)? I really never tried to sum() strings before, but it makes sense that, if sum() already checks if the argument is a string before, it should do the "".join instead of returning an error. Also, why is there a special case for the strings, but not for the tuples? Doesn't sum(((1,) for _ in xrange(100)),()) also have quadratic behaviour, creating and destroying intermediate tuples? And what happens with lists? -- Luis Zarrabeitia (aka Kyrie) Fac. de Matemática y Computación, UH. http://profesores.matcom.uh.cu/~kyrie -- http://mail.python.org/mailman/listinfo/python-list
