Terminal generator output

Question

I have a mental block, is there a regular python 1-liner to stop comprehension of a list or genex based on some condition? Usage example:

def primes(): # yields forever eg 2, 3, 5, 7, 11, 13 ... [p for p in primes() if p < 10] # will never terminate, and will go onto infinite loop consuming primes() [p for p in primes() while p < 10] # should return [2, 3, 5, 7], and consumed 5 items from my generator 

I know about itertools consumes, islice , but these guys require you to know how many items you want to consume in advance.

Answer 1

You can use itertools.takewhile :

 itertools.takewhile(lambda x: x < 10, primes()) 

or ... if you want to avoid lambda:

 itertools.takewhile((10.).__gt__, primes())