Python itertools.ifilter is efficient way of filtering and looping over a large iterable. Here is the usage for ifilter:
The function should take one argument and should return boolean value. If true is returned for a value, that value is taken.
Here are some examples.
ifilter on list using function
Given a list of numbers get a new iterable with items less than 100.
import itertools def is_lt_100(x): return x < 100 a = [1,2,3,4,1000] b = itertools.ifilter(is_lt_100, a) print b for i in b: print i
<itertools.ifilter object at 0x7f172356b9d0> 1 2 3 4
ifilter on list using lambda
import itertools a = [1,2,3,4,1000] b = itertools.ifilter(lambda x: x < 100, a) print b for i in b: print i
<itertools.ifilter object at 0x7f9c568d49d0> 1 2 3 4