Sort a list by multiple attributes? Sort a list by multiple attributes? python python

# Sort a list by multiple attributes?

A key can be a function that returns a tuple:

``s = sorted(s, key = lambda x: (x, x))``

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

``import operators = 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))``

I'm not sure if this is the most pythonic method ...I had a list of tuples that needed sorting 1st by descending integer values and 2nd alphabetically. This required reversing the integer sort but not the alphabetical sort. Here was my solution: (on the fly in an exam btw, I was not even aware you could 'nest' sorted functions)

``a = [('Al', 2),('Bill', 1),('Carol', 2), ('Abel', 3), ('Zeke', 2), ('Chris', 1)]  b = sorted(sorted(a, key = lambda x : x), key = lambda x : x, reverse = True)  print(b)  [('Abel', 3), ('Al', 2), ('Carol', 2), ('Zeke', 2), ('Bill', 1), ('Chris', 1)]``

Several years late to the party but I want to both sort on 2 criteria and use `reverse=True`. In case someone else wants to know how, you can wrap your criteria (functions) in parenthesis:

``s = sorted(my_list, key=lambda i: ( criteria_1(i), criteria_2(i) ), reverse=True)``