Re^2: Concatenate or Join?


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Re^2: Concatenate or Join?

by tobyink (Canon)

on Nov 12, 2012 at 20:54 UTC ( [id://1003507]=note: print w/replies, xml )

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in reply to Re: Concatenate or Join?
in thread Concatenate or Join?

It depends what you're doing really. In your example, join beats concat, but that's because you are looping through an array. Here though, concatenation beats it (albeit only by about 10%):

use strict;
use warnings;
use Benchmark qw{ cmpthese };

sub foo { 'abc' };
sub bar { 'def' };

cmpthese( -3, {
    concat => sub { my $ret = foo().bar(); return $ret; },
    join   => sub { my $ret = join q{}, foo(), bar(); return $ret; },
});
[download]

And here (thanks to the Perl compiler being so good at constant folding) concatenation is more than twice as fast as join:

use strict;
use warnings;
use Benchmark qw{ cmpthese };

sub foo () { 'abc' };
sub bar () { 'def' };

cmpthese( -3, {
    concat => sub { my $ret = foo . bar; return $ret; },
    join   => sub { my $ret = join q{}, foo, bar; return $ret; },
});
[download]

perl -E'sub Monkey::do{say$_,for@_,do{($monkey=[caller(0)]->[3])=~s{::}{ }and$monkey}}"Monkey say"->Monkey::do'