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use strict;
use warnings;

...

my $h = 'my $i = sub { print map {$_ *= 2; "$_ ";} @f; print "\n" }; $
+i->();';
eval ($h);

use strict;
use warnings;
use Benchmark;
...
    "idiomatic" => q[     $_ +=2 for @array2; ],
    "map"       => q[ map $_ +=2,    @array2; ],
};

Benchmark: timing 50000 iterations of idiomatic, map...
 idiomatic:  3 wallclock secs ( 2.87 usr +  0.00 sys =  2.87 CPU) @ 17
+421.60/s (
n=50000)
...
n=50000)
       map:  3 wallclock secs ( 3.04 usr +  0.00 sys =  3.04 CPU) @ 16
+436.55/s (
n=50000)