Sort a list by multiple attributes?

Question

I have a list of lists:

[[12, 'tall', 'blue', 1], [2, 'short', 'red', 9], [4, 'tall', 'blue', 13]] 

If I wanted to sort by one element, say the tall/short element, I could do it via s = sorted(s, key = itemgetter(1)).

If I wanted to sort by both tall/short and colour, I could do the sort twice, once for each element, but is there a quicker way?

Answer 1

A key can be a function that returns a tuple:

s = sorted(s, key = lambda x: (x[1], x[2])) 

Or you can achieve the same using itemgetter (which is faster and avoids a Python function call):

import operator s = sorted(s, key = operator.itemgetter(1, 2)) 

And notice that here you can use sort instead of using sorted and then reassigning:

s.sort(key = operator.itemgetter(1, 2))