Kottiyath <n.kottiy...@gmail.com> writes: > I have the following list of tuples: > L = [(1, 2), (3, 4, 5), (6, 7)] > > I want to loop through the list and extract the values. > The only algorithm I could think of is: >>>> for i in l: > ... u = None > ... try: > ... (k, v) = i > ... except ValueError: > ... (k, u, v) = i > ... print k, u, v > --------- > 1 None 2 > 3 4 5 > 6 None 7 > ------------- > But, this algorithm doesnt look very beautiful - like say -> for k, u, > v in L: > Can anyone suggest a better algorithm to get the values?
Just a note: this isn't really an algorithm problem. ;) It's more of a grammar obstruction. To make your code more simple, it would be nice if the assignment operator would return, "None," in the case where there are too few values to unpack from the right-operand of the assignment operator. Aside from the typical workarounds that first came to mind, I started wondering whether it was possible to expose the problem and solve it directly. Sadly, it appears to be non-trivial (or at least, well hidden from the unwashed masses). I'd be really curious if the unpacking machinery were exposed to the developer. I started poking around the operator and types modules, but the implementation isn't obvious. What methods are being called on the operands by the assignment operator in the following statement: a, b, c = some_tuple I'm sorry if this line of inquiry is not very pythonic; but one is curious if this is some python magic happening here. After using the idiom for years I hadn't really thought about it much until recently. -- http://mail.python.org/mailman/listinfo/python-list
