From: "John W. Krahn" <[EMAIL PROTECTED]>
> Peter Scott wrote:
> > In article <[EMAIL PROTECTED]>,
> > [EMAIL PROTECTED] (Edward Wijaya) writes:
> >
> >>BTW, can you explain what's the difference between these two?
> >>
> >>>sub hamming_distance_string { ( $_[0] ^ $_[1] ) =~ tr/\0// }
> >
> > In a scalar context, tr/// returns the count of the number of
> > characters seen.
> >
> >>>sub hamming_distance_string { () = ( $_[0] ^ $_[1] ) =~ /\0/g }
> >
> >>From inside to out: make the global match on the XOR result.
> > We want this to be in a list context so that all of them are made,
> > but we don't need there to be anything in the list assigned, so we
> > use the empty list (). This subroutine must be called in a scalar
> > context, because the result of a list assignment in scalar context
> > is the number of things assigned, i.e., the number of matches.
> > Elegant, but... somewhat advanced.
>
> Yes, you're right, I should have assigned to a scalar to avoid any
> confusion about the calling context. :-)
>
> sub hamming_distance_string { my $ret = ( $_[0] ^ $_[1] ) =~ tr/\0//;
> $ret }
sub hamming_distance_string { scalar( ( $_[0] ^ $_[1] ) =~ tr/\0//) }
would be enough :-)
Jenda
===== [EMAIL PROTECTED] === http://Jenda.Krynicky.cz =====
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to get drunk and croon as much as they like.
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