I think the best way is
What's your definition of "best way"? split // seems to be the most common idiom. And the "ugly" way, use of substr seems to be the fastest according to the following benchmark: 
#!/usr/bin/perl

use strict;
use warnings;

use Benchmark qw /timethese cmpthese/;

our $char;

for my $size (4, 16, 64, 256, 1024) {
    print "Iterating over a string of length $size.\n";

    our $str = "-" x $size;

    cmpthese -5  => {
        split    => 'for my $c (split // => $str) {$char = $c}',
        for      => 'for my $c ($str =~ /(.)/g)   {$char = $c}',
        while    => 'while ($str =~ /(.)/g)       {$char = $1}',
        substr   => 'for my $i (0 .. (length ($str) - 1))
                                                  {$char = substr $str
+, $i, 1}',
    }
}

__END__
Iterating over a string of length 4.
           Rate  split    for  while substr
split  157193/s     --    -9%   -20%   -44%
for    173109/s    10%     --   -12%   -38%
while  197371/s    26%    14%     --   -30%
substr 280339/s    78%    62%    42%     --
Iterating over a string of length 16.
           Rate  split    for  while substr
split   47828/s     --    -3%   -12%   -55%
for     49213/s     3%     --   -10%   -54%
while   54413/s    14%    11%     --   -49%
substr 107090/s   124%   118%    97%     --
Iterating over a string of length 64.
          Rate  split    for  while substr
split  12882/s     --    -5%    -7%   -56%
for    13574/s     5%     --    -2%   -54%
while  13798/s     7%     2%     --   -53%
substr 29595/s   130%   118%   114%     --
Iterating over a string of length 256.
         Rate  split    for  while substr
split  3244/s     --    -5%    -7%   -59%
for    3420/s     5%     --    -2%   -57%
while  3483/s     7%     2%     --   -56%
substr 7951/s   145%   132%   128%     --
Iterating over a string of length 1024.
         Rate  split    for  while substr
split   818/s     --    -4%    -7%   -59%
for     850/s     4%     --    -3%   -58%
while   875/s     7%     3%     --   -57%
substr 2013/s   146%   137%   130%     --

[download]
I must say, the performance of substr surprises me, and I find the difference between substr and other methods suspect, but I can't find any flaw in the benchmark.

Abigail

In reply to Re: foreach (each character in string..)? by Abigail-II
in thread foreach (each character in string..)? by Anonymous Monk

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