Re^2: map vs for\foreach.

In my case:

foreach(@a){$_+=1;};


real    0m3.756s
user    0m3.588s
sys    0m0.120s
[download]

map{$_+= 1} @a;

real    0m5.233s
user    0m5.056s
sys    0m0.164s
[download]

Comment on Re^2: map vs for\foreach. Select or Download Code

Replies are listed 'Best First'.
Re^3: map vs for\foreach. by sn1987a (Curate) on Mar 11, 2015 at 15:12 UTC
My previous timings where just from a single run of each program. Using Benchmark and repeating to verify consistent results, I find that `foreach` is indeed faster. `use strict; use warnings; use Benchmark; my @a; $a[$_] = int( rand(100) ) for ( 0 .. 10000000 ); cmpthese( -30, { 'foreach' => sub { foreach (@a) { $_ += 1; } }, 'map (assign)' => sub { @a = map { $_ += 1 } @a; }, 'map (bare)' => sub { map { $_ += 1 } @a; }, } );` [download] Results: `s/iter map (assign) map (bare) foreach map (assign) 2.06 -- -40% -76% map (bare) 1.23 67% -- -59% foreach 0.501 311% 146% --` [download]	[reply] [d/l] [select]

Replies are listed 'Best First'.

Re^3: map vs for\foreach.
by sn1987a (Curate) on Mar 11, 2015 at 15:12 UTC

My previous timings where just from a single run of each program. Using Benchmark and repeating to verify consistent results, I find that foreach is indeed faster.

use strict;
use warnings;
use Benchmark;

my @a;
$a[$_] = int( rand(100) ) for ( 0 .. 10000000 );

cmpthese(
    -30,
    {
        'foreach'      => sub { foreach (@a) { $_ += 1; } },
        'map (assign)' => sub { @a = map { $_ += 1 } @a; },
        'map (bare)'   => sub { map { $_ += 1 } @a; },
    }
);
[download]

Results:

             s/iter map (assign)   map (bare)      foreach
map (assign)   2.06           --         -40%         -76%
map (bare)     1.23          67%           --         -59%
foreach       0.501         311%         146%           --
[download]

[reply]
[d/l]
[select]