bit count or bit set && Python3

[Terry Reedy]

On 10/25/2012 12:13 PM, rusi wrote:
> On Oct 25, 7:56 pm, Charles Hixson <charleshi... at earthlink.net> 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 I wanted 1000s of fast limited-length bitsets, I would consider using 
Cython to make an extension class.

-- 
Terry Jan Reedy