["python","list"]
How to find the last occurrence of an item in a Python list

Say I have this list: li = ["a", "b", "a", "c", "x", "d", "a", "6"] As far as help showed me, there is not a builtin function that returns the last occurrence of a string (like the reverse of index). So basically, how can I find the last occurrence of "a" in the given list?
If you are actually using just single letters like shown in your example, then str.rindex would work handily. This raises a ValueError if there is no such item, the same error class as list.index would raise. Demo: >>> li = ["a", "b", "a", "c", "x", "d", "a", "6"] >>> ''.join(li).rindex('a') 6 For the more general case you could use list.index on the reversed list: >>> len(li) - 1 - li[::-1].index('a') 6 The slicing here creates a copy of the entire list. That's fine for short lists, but for the case where li is very long, it may be more efficient to use a reverse iteration and avoid the copy: def list_rindex(li, x): for i in reversed(range(len(li))): if li[i] == x: return i raise ValueError("{} is not in list".format(x)) One-liner version: next(i for i in reversed(range(len(li))) if li[i] == 'a')