pythonic way to rewrite an assignment in an if statement

Question

Is there a pythonic preferred way to do this that I would do in C++:

for s in str:
    if r = regex.match(s):
        print r.groups()

I r

Answer 1

Whenever I find that my loop logic is getting complex I do what I would with any other bit of logic: I extract it to a function. In Python it is a lot easier than some other languages to do this cleanly.

So extract the code that just generates the items of interest:

def matching(strings, regex):
    for s in strings:
        r = regex.match(s)
        if r: yield r

and then when you want to use it, the loop itself is as simple as they get:

for r in matching(strings, regex):
    print r.groups()