On Thu, Oct 25, 2012 at 9:24 AM, Mark Lawrence <breamore...@yahoo.co.uk>wrote:
> On 25/10/2012 15:47, Charles Hixson wrote: > >> In Python3 is there any good way to count the number of on bits in an >> integer (after an & operation)? >> Alternatively, is there any VERY light-weight implementation of a bit >> set? I'd prefer to use integers, as I'm probably going to need >> thousands of these, if the tests work out. But before I can test, I >> need a decent bit counter. (shift, xor, &, and | are already present >> for integer values, but I also need to count the number of "true" items >> after the logical operation. So if a bitset is the correct approach, >> I'll need it to implement those operations, or their equivalents in >> terms of union and intersection.) >> >> Or do I need to drop into C for this? >> >> > If needed bitarray and bitstring are available on pypi. > There's also my bits_mod.py: http://stromberg.dnsalias.org/svn/bits/trunk/ I separated it out of my bloom filter code recently, to facilitate a prime number sieve. Behind the scenes it's an array of int's.
-- http://mail.python.org/mailman/listinfo/python-list
