Get the index of an element in a queryset

Question

I have a QuerySet, let's call it qs, which is ordered by some attribute which is irrelevant to this problem. Then I have an object, let's call it obj. Now I'd like to know at what index obj has in qs, as efficiently as possible. I know that I could use .index() from Python or possibly loop through qs comparing each object to obj, but what is the best way to go about doing this? I'm looking for high performance and that's my only criteria.

Using Python 2.6.2 with Django 1.0.2 on Windows.

Answer 1

If you're already iterating over the queryset and just want to know the index of the element you're currently on, the compact and probably the most efficient solution is:

for index, item in enumerate(your_queryset):     ... 

However, don't use this if you have a queryset and an object obtained by some unrelated means, and want to learn the position of this object in the queryset (if it's even there).