comment on

Sorry for the delay in getting back to you. I've adapted your technique somewhat:

sub eily{
    my $str = shift;
    my @b = map[ ( 1e99, 0 ) x 2 ], 1 .. 256;

    for my $y ( 0 .. $HEIGHT-1 ) {
        my $s = \substr( $$str, $y * $WIDTH, $WIDTH );
        my $t = ' ' . $$s ^ $$s;
        chop $t;
        while( $t  =~ m[[^\0]\0*]g ) {
            my $c = ord substr $$s, $-[0], 1; #, $-[0], $+[0];
            $b[ $c ][ LEFT   ] = $-[0]   if  $-[0]    < $b[ $c ][ LEFT
+   ];
            $b[ $c ][ RIGHT  ] = $+[0]-1 if  $+[0]-1  > $b[ $c ][ RIGH
+T  ];
            $b[ $c ][ TOP    ] = $y      if        $y < $b[ $c ][ TOP 
+   ];
            $b[ $c ][ BOTTOM ] = $y      if        $y > $b[ $c ][ BOTT
+OM ];
        }
    }
    return \@b;
}
[download]

and the results are impressive:

C:\test>\perl22\bin\perl 1176081.pl -WIDTH=10000 -HEIGHT=10000
yr() took 12.478694
buk3() took 8.195635
dave() took 1.876719
eily took 0.888511

C:\test>\perl22\bin\perl 1176081.pl -WIDTH=20000 -HEIGHT=20000
yr() took 18.774189
buk3() took 32.063918
dave() took 5.701784
eily took 2.409520
[download]

With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'

Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.

"Science is about questioning the status quo. Questioning authority". The enemy of (IT) success is complexity.

In the absence of evidence, opinion is indistinguishable from prejudice.

In reply to Re^4: Faster regex to split a string into runs of similar characters? by BrowserUk
in thread Faster regex to split a string into runs of similar characters? by BrowserUk

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