our @array2 = 1 .. 1000;
timethese 10000, {
    "idiomatic" => q[     $_ +=2 for @array2; ],
    "map"       => q[ map $_ +=2,    @array2; ],
};

__END__
Benchmark: timing 10000 iterations of idiomatic, map...
 idiomatic:  1 wallclock secs ( 0.88 usr +  0.00 sys =  0.88 CPU) @ 11428.57/s (n=10000)
       map:  1 wallclock secs ( 0.84 usr +  0.00 sys =  0.84 CPU) @ 11848.34/s (n=10000)