Re: comparing two binary numbers

Johnson Lau wrote:
> Dear all,

Hello,

> I need to compare two binary numbers and need perl to return the
> number of matching bits.
> 
> For example:
> 
> $aaa = "10111100";
> $bbb = "00101100";

Those aren't binary numbers, they are strings.

perldoc perlnumber

> In this case, the number of matching bits is 6.
> 
> I know I could split the strings and compare the bits one by one.
> However, is there any faster functions for this? I need to compare
> millions of such strings with 1000 bits for each.

If you actually had "binary" numbers then you could use unpack( '%32b*', 
$var ) to count bits.

perldoc perlpacktut



John
-- 
Perl isn't a toolbox, but a small machine shop where you
can special-order certain sorts of tools at low cost and
in short order.                            -- Larry Wall