Sequence find function in Python

Question

How do I find an object in a sequence satisfying a particular criterion?

List comprehension and filter go through the entire list. Is the only alternative a handmade

Answer 1

Actually, in Python 3, at least, filter doesn't go through the entire list.

To double check:

def test_it(x):
    print(x)
    return x>10

var = next(filter(test_it, range(20)))

In Python 3.2, that prints out 0-11, and assigns var to 11.

In 2.x versions of Python you may need to use itertools.ifilter.