$$vars{'test'} is a visual pain for me because of the split millisecond where I ask myself about precedence. OTH the -> in $vars->{'test'} dates back to at least C where is used in exactly the same way and context.
Performance-wise I don't think there is a difference (OSX 10.13 and perl 5.28.3):
use Benchmark qw( cmpthese );
cmpthese(-5, {
deref => 'use strict; use warnings; my $x = { map { $_ => rand
+ } 1..50 };
$x->{$_} = $_ for 1..100',
none => 'use strict; use warnings; my $x = { map { $_ => rand
+ } 1..50 };
$$x{$_} = $_ for 1..100'
});
Rate deref none
deref 12483/s -- -1%
none 12611/s 1% --
Rate none deref
none 11938/s -- -0%
deref 11967/s 0% --
Or,
use Benchmark qw( cmpthese );
cmpthese(-5, {
deref => 'use strict; use warnings;
srand 42;
my $x = { map { rand() => rand() } 1..50 };
srand 42;
$x->{rand()} = rand() for 1..100',
none => 'use strict; use warnings;
srand 42;
my $x = { map { rand() => rand() } 1..50 };
srand 42;
$$x{rand()} = rand() for 1..100'
});
For benchmarks see also: https://stackoverflow.com/questions/18984323/how-expensive-is-it-to-dereference-an-array-ref-in-perl
bw, bliako
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