is_anagram

from collections import Counter
from itertools import islice, tee

def sliding_counter(iterable, window):
    'generates counts for iterable in window, starting at position 0, 1, ...'
    ita, itb = tee(iter(iterable))
    c = Counter(islice(itb, window))
    while 1:
        yield c
        c[next(ita)] -= 1
        c[next(itb)] += 1

def is_anagram(first, second):
    'ís a part of the second word an anagram of the first word?'
    target = Counter(first)
    return any(not (a - target) for a in sliding_counter(second, len(first)))

print is_anagram("trel", "appletree") # True
print is_anagram("reel", "appletree") # False
print is_anagram("diep", "parallellepipedum") # True
print is_anagram("dier", "parallellepipedum") # False
print is_anagram("pparallelle", "parallellepipedum") # True
print is_anagram(" gnimP", "Programming Praxis") # True