How to use the quick sort to sort by index in a list of a list

Question

I am trying to use a quick sort to sort through a list of lists at index [1]. For example:

list = [[2, 5, 3],
        [2, 4, 9],
        [0, 9, 1],
        [1, 1         


        

Answer 1

You want to use the key argument in list.sort:

import operator
mylist = [[2, 5, 3],
          [2, 4, 9],
          [0, 9, 1],
          [1, 1, 1],
          [4, 7, 5]]

mylist.sort(key=operator.itemgetter(1))

Output:

>>> mylist = [[2, 5, 3],
...           [2, 4, 9],
...           [0, 9, 1],
...           [1, 1, 1],
...           [4, 7, 5]]
>>> 
>>> mylist.sort(key=operator.itemgetter(1))
>>> mylist
[[1, 1, 1], [2, 4, 9], [2, 5, 3], [4, 7, 5], [0, 9, 1]]