The most generic way to do this is simply to sort separately by each key in turn. Python’s sorting is always stable so it is safe to do this:
sort(data, key=tiebreakerkey) sort(data, key=datekey, reverse=True)
will (assuming the relevant definitions for the key functions) give you the data sorted by descending date and ascending tiebreakers.
Note that doing it this way is slower than producing a single composite key function because you will end up doing two complete sorts, so if you can produce a composite key that will be better, but splitting it out into separate sorts gives a lot of flexibility: given a key function for each column you can make any combination of them and specify reverse for any individual column.
For a completely generic option:
keys = [ (datekey, True), (tiebreakerkey, False) ] for key, rev in reversed(keys): sort(data, key=key, reverse=rev)
and for completeness, though I really think it should be avoided where possible:
from functools import cmp_to_key sort(data, key=cmp_to_key(your_old_comparison_function))
The reason I think you should avoid this you go back to having
n log n calls to the comparison function compared with
n calls to the key function (or
2n calls when you do the sorts twice).