Jeff Peery wrote: > ... what is '*' in '*temp'? thanks! Say you have a function of 3 arguments: In [1]: def add(a, b, c): ...: return a+b+c
Normally to call it, you just specify the three arguments: In [2]: add(1, 2, 3) Out[2]: 6 Suppose the arguments were already in a list, what would you do? You can't just pass the list, that is a single argument and you need three: In [3]: data=[1, 2, 3] In [4]: add(data) ------------------------------------------------------------ Traceback (most recent call last): File "<ipython console>", line 1, in <module> <type 'exceptions.TypeError'>: add() takes exactly 3 arguments (1 given) You could unpack the data yourself: In [5]: a, b, c = data In [6]: add(a, b, c) Out[6]: 6 Or you can use the * notation, which basically means, "treat each element of this list as a separate argument", or "use this list as the argument list directly": In [7]: add(*data) Out[7]: 6 If the length of the argument list (data, in the example above) can change, manually unpacking the list won't work and the * syntax is the only alternative. Kent > Decorate-sort-undecorate > (http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/52234) > to the rescue: > > In [12]: a = [3,2,1,4] > In [13]: b = ['hi', 'my','name', 'is'] > In [14]: c = [5,2,4,2] > In [15]: temp = zip(a, b, c) > In [16]: temp > Out[16]: [(3, 'hi', 5), (2, 'my', 2), (1, 'name', 4), (4, 'is', 2)] > In [17]: temp.sort() > In [18]: _, b, c = zip(*temp) > In [19]: b > Out[19]: ('name', 'my', 'hi', 'is') > In [20]: c > Out[20]: (4, 2, 5, 2) _______________________________________________ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor