Re: foreach (each character in string..)?

Just for a change, a different (less perlish, maybe) way is to use an index to extract a single character, more or less like this:

my $c;
for ( my $i = 0; $i < length($string); $i++ ) { 
    $c = substr( $string, $i, 1);
}
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I would not usually favour it for style and readability that are much better in the split version, but I posted it for completeness.

By the way, I noticed that the execution speed is more or less the same; I measured this with Benchmark, and noticed that the longer the string in $string, the comparatively fast the for version gets.

See how the bigger the input $string gets, the bigger the difference in favour of the for version is, going from +5% to +16% in the 30k case.

$string is 3000 bytes
Benchmark: running for, split, each for at least 10 CPU seconds...
       for: 10 wallclock secs (10.31 usr +  0.00 sys = 10.31 CPU) @ 12
+3.73/s (n=1275)
     split: 10 wallclock secs (10.58 usr +  0.00 sys = 10.58 CPU) @ 11
+7.15/s (n=1240)

+5%

$string is 10000 bytes
Benchmark: running for, split, each for at least 10 CPU seconds...
       for: 11 wallclock secs (10.33 usr +  0.00 sys = 10.33 CPU) @ 36
+.96/s (n=382)
     split: 11 wallclock secs (10.44 usr +  0.00 sys = 10.44 CPU) @ 34
+.08/s (n=356)

+8%

$string is 30000 bytes
Benchmark: running for, split, each for at least 10 CPU seconds...
       for: 10 wallclock secs (10.19 usr +  0.00 sys = 10.19 CPU) @ 12
+.36/s (n=126)
     split: 10 wallclock secs (10.60 usr +  0.00 sys = 10.60 CPU) @ 10
+.57/s (n=112)
     
+16%
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This is my test code:

use Benchmark;
my $string = "1234567890" x 5000 ;

print "\$string is " . length( $string ) . " bytes \n";

timethese(-10,{split=>sub{  
                    for my $c (split //, $string) {  }   
                      },
             for=>sub{ 
             
                    my $c;
                    for ( my $i = 0; $i < length($string); $i++ ) { 
                        $c = substr( $string, $i, 1);
                    }
             
              }});
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