Use m?alpha? instead of m/alpha/ to match only once:

#!/usr/bin/perl

use warnings;
use strict;

while (<DATA>) {
    if (m?alpha?) {
        print "+ $_";
    } else {
        print "- $_";
    }
}

__DATA__
beta
beta
alpha
beta
beta
alpha
alpha
beta

[download]

Results in:

- beta
- beta
+ alpha
- beta
- beta
- alpha
- alpha
- beta

[download]

In reply to Re: A way to avoid repeated conditional loops by Anonymous Monk
in thread A way to avoid repeated conditional loops by Deus Ex

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