On Aug 19, 4:19 pm, Neal Becker <ndbeck...@gmail.com> wrote: > What would be a time efficient way to count the number of occurrences of > elements of sequence A in sequence B? (in this particular case, these > sequences are strings, if that matters).
Python 3.1.1 (r311:74483, Aug 17 2009, 17:02:12) [MSC v.1500 32 bit (Intel)] on win32 Type "copyright", "credits" or "license()" for more information. >>> import collections >>> A = 'abc' >>> B = 'abracadabra' >>> collections.Counter(filter(set(A).__contains__, B)) Counter({'a': 5, 'b': 2, 'c': 1}) Raymond -- http://mail.python.org/mailman/listinfo/python-list