Python list.index() from end of the list

Question

In python, if I have a list say [2,1,1,3,5], then is it possible to get

[2,1,1,3,5].index(1) as 2 i.e first match starting from the higher end instead of the lower?

possible duplicate of [Equivelant to rindex for lists in Python](http://stackoverflow.com/questions/9836425/equivelant-to-rindex-for-lists-in-python) — alecxe, Apr 01 '14 at 18:01
Yeah, its a duplicate of http://stackoverflow.com/questions/6890170/python-how-to-find-last-occurrence-in-a-list-in-python , could someone close it? — user80551, Apr 01 '14 at 18:04

Adam Smith · Answer 1 · 2014-04-01T18:01:07.220

1

Can't say I've ever needed to do this, but you could always hack it with:

lst = [2,1,1]
reverseindex = len(lst)-1 - lst[::-1].index(1)

Note that if you had a STRING, you could do:

string = "21135"
reverseindex = string.rindex(1)
# reverseindex == 2

But lists don't have this function.

edited Apr 01 '14 at 18:01

answered Apr 01 '14 at 17:54

Adam Smith

score 0 · Answer 2 · answered Apr 01 '14 at 18:02

0

If you don't care about list order being preserved, you could always use lst.reverse() before lst.index(1).

answered Apr 01 '14 at 18:02

Daniel Kotin

The documentation does not even say that `list.index()` has a start_at attribute – user80551 Apr 01 '14 at 18:06

2 Answers2