use strict;

use Benchmark 'cmpthese';

my @y_vals = my @x_vals = 1 .. 50;
cmpthese(-10, {
  map => sub {
    return map "($x_vals[$_],$y_vals[$_])", 0 .. $#x_vals
  },
  for => sub {
    my @ret;
    $ret[$_] = "($x_vals[$_],$y_vals[$_])"
      for 0 .. $#x_vals;
    return @ret;
  },
});

__output__

Benchmark: running for, map, each for at least 10 CPU seconds...
       for: 11 wallclock secs (10.19 usr +  0.00 sys = 10.19 CPU) @ 7536.80/s (n=76800)
       map: 11 wallclock secs (10.34 usr +  0.01 sys = 10.35 CPU) @ 7768.31/s (n=80402)
      Rate for map
for 7537/s  -- -3%
map 7768/s  3%  --