Nope, worse. The map still loops just like a for loop would have to, but it also has to manipulate an argument stack (or something like it) so that it can set the $_ and then return it. I'm really not very sure about what I just said, but it is my understanding that is the case.

The only way to know for sure it so try it. 

use strict;
use Benchmark qw(cmpthese);

my @a1 = (1 .. 4_000);

cmpthese(4_000, {
    for_loops => sub { for(@a1) { $_ = $_ + 1 } },
    map_loops => sub { map { $_ = $_ + 1 } @a1  },
});

[download]
           Rate map_loops for_loops
map_loops 499/s        --      -40%
for_loops 835/s       67%        --

[download]

-Paul

In reply to Re^3: Scanning a list for indices by jettero
in thread Scanning a list for indices by cmv

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