Find first sequence item that matches a criterion [duplicate]
If you don't have any other indexes or sorted information for your objects, then you will have to iterate until such an object is found:
next(obj for obj in objs if obj.val == 5)
This is however faster than a complete list comprehension. Compare these two:
[i for i in xrange(100000) if i == 1000]next(i for i in xrange(100000) if i == 1000)
The first one needs 5.75ms, the second one 58.3µs (100 times faster because the loop 100 times shorter).