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Date: Fri, 26 Oct 2012 08:42:54 -0700 (PDT)
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Subject: Re: bit count or bit set && Python3
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Xref: csiph.com comp.lang.python:32221

On Thursday, October 25, 2012 7:56:25 AM UTC-7, Charles Hixson wrote:
> In Python3 is there any good way to count the number of on bits in an 
> integer (after an & operation)?

You may want to look at gmpy2[1] and the popcount() function.

> 
> 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, 
> 

Whether or not gmpy2 is considered light-weight is debateable. :)

> 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?
> 

[1] http://code.google.com/p/gmpy/

> 
> 
> -- 
> 
> Charles Hixson