> I have 2 lists
> a = [(4, 1), (7, 3), (3, 2), (2, 4)]
> b = [2, 4, 1, 3]
>
> Now, I want to order _a_ (a[1]) based on _b_.
> i.e. the second element in tuple should be the same as
> b.
> i.e. Output would be [(3, 2), (2, 4), (4, 1), (7, 3)]
>
> I did the same as follows:
> >>> l = len(a) * [None]
> >>> for (k, v) in a:
> ... for i, e in enumerate(b):
> ... if e == v:
> ... l[i] = (k, v)
>
Essentially, you're sorting a list. The Pythonic approach is to use the sort()
function, hiding the details in a "custom comparison function":
def compare_func(first, second):
b = [2, 4, 1, 3]
return cmp(b.index(first[1]), b.index(second[1]))
if __name__ == '__main__':
a = [(4, 1), (7, 3), (3, 2), (2, 4)]
a.sort(cmp=compare_func)
print a
-John
--
http://mail.python.org/mailman/listinfo/python-list
