Question

Is there a more pythonic way, or at least a shorter and simpler way, to do this:

i = 1
while True:
    res = lookup(i) # returns a value or None
    if res is None:
        break
    else:
        i += 1
        yield res

Answer 1

You could make use of itertools:

from itertools import takewhile, count

# ...
def myfunc():
    return takewhile(lambda x: x is not None, (lookup(i) for i in count(1)))

If you don’t like takewhile for whatever reason:

for i in count(1):
     res = lookup(i)
     if res is None: break
     yield res