Complex sort with multiple parameters?

Question

I have a list of tuples:

li = [('fink', 3), ('flip', 3), ('flock', 4), ('foo', 12), ('foot', 20), ('football', 20), ('futz', 10), ('flip', 3), ('flank', 3), ('flop', 3)]

How can I sort the list by descent number first and then alphabetically descending? The results would be:

('foot', 20)
('football', 20)
('foo', 12)
('futz', 10)
('flock', 4)
('fink', 3)
('flip', 3)
('flake', 3)
('flop', 3)

from operator import itemgetter

sorted_li = sorted(li, key=itemgetter(1,0), reverse=True)

While the above code sorts by descending number correctly, the words are not sorted alphabetically.

possible duplicate of Advanced sorting criteria for a list of nested tuples — eumiro
– eumiro, Commented Jul 12, 2012 at 11:02

eumiro · Accepted Answer · 2012-07-12 11:01:24Z

11

This is too complicated for a single itemgetter. Use lambda instead:

sorted_li = sorted(li, key=lambda x: (-x[1], x[0]))

It is about the same speed as two consecutive sorts using itemgetter, but it is less code and probably more readable.

edited Jul 12, 2012 at 11:01

answered Jul 12, 2012 at 10:55

eumiro

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2 Comments

Jon Clements Over a year ago

This works because you're able to use the fact a sort element is a number. What if both were strings?

jamylak Over a year ago

@JonClements He would use your solution :)

Jon Clements · Accepted Answer · 2012-07-12 10:54:56Z

6

As Python's sort is stable, it's easiest to sort twice:

sorted_li  = sorted(li, key=itemgetter(1), reverse=True)
sorted_li.sort(key=itemgetter(0))

answered Jul 12, 2012 at 10:54

Jon Clements

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Comments

Nariman Jafari · Accepted Answer · 2018-12-10 22:48:49Z

0

As Python's sort is stable, it's easiest to sort twice:

sorted_li  = sorted(li, key=itemgetter(0))
sorted_li.sort(key=itemgetter(1), reverse=True)

but attention that you must use your lowest priority order at first , then the others base on the priority. the highest priority order must be the last one. it is the most important thing that you have to consider when you try to use Sorted function.

answered Dec 10, 2018 at 22:48

Nariman Jafari

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