Python sorting key function supporting tuples and lists

Question

In Python you can for example sort tuples sorted([(2,2),(1,2),(2,1),(1,1)]) and get [(1, 1), (1, 2), (2, 1), (2, 2)].

You can also use custom k

Answer 1

You could create a mapper function, that takes your key function and returns another function, applying the key function to each element of some iterable.

def mapper(function):
    def inner(values):
        return tuple([function(x) for x in values])
    return inner

Example:

>>>sorted([('Gold', 2), ('Bronze', 1), ('Gold', 1)], key=mapper(custom_key))
[('Gold', 1), ('Gold', 2), ('Bronze', 1)]

Or similar, using functools.partial with map:

>>> sorted([('Gold', 2), ('Bronze', 1), ('Gold', 1)], key=functools.partial(map, custom_key))
[('Gold', 1), ('Gold', 2), ('Bronze', 1)]