next_n

Suppose you want to find the next n elements of a stream the matches a predicate.

(I just used it in web scraping with BeautifulSoup to get the next 5 sibling "tr" for a table).

#!/usr/bin/env python

from itertools import ifilter, islice

def next_n(items, pred, count):
 return islice(ifilter(pred, items), count)

if __name__ == "__main__":
 from gmpy import is_prime
 from itertools import count
 for prime in next_n(count(1), is_prime, 10):
     print prime

Will print

2
3
5
7
11
13
17
19
23
29

(Using gmpy for is_prime)