Question

I need to sort a list and then return a list with the index of the sorted items in the list. For example, if the list I want to sort is [2,3,1,4,5], I need [2,0,1,3,4] to be returned.

This question was posted on bytes, but I thought I would repost it here.
http://bytes.com/topic/python/answers/44513-sorting-list-then-return-index-sorted-item

My specific need to sort a list of objects based on a property of the objects. I then need to re-order a corresponding list to match the order of the newly sorted list.

Is there a good way to do this?

Answer 1

You can use the python sorting functions’ key parameter to sort the index array instead.

>>> s = [2, 3, 1, 4, 5, 3]
>>> sorted(range(len(s)), key=lambda k: s[k])
[2, 0, 1, 5, 3, 4]
>>>