If you don't care about order, replacing the deleted element by the last in the array works as well. And I was expecting it to be faster than splice (since I was expecting the latter to move every element after the one that is removed) but the performances are actually very similar:
use warnings;
use strict;
use Benchmark qw/cmpthese/;
my $size = 1e3;
my @numbers = ( 0..$size );
my $index = 3;
my @expect = ( 0..2,4..$size );
use constant TEST => 0;
cmpthese(-2, {
splice => sub {
my @output = @numbers;
splice @output, $index, 1;
join("\0", sort @output) eq join("\0", sort @expect) or die if TES
+T;
},
grep => sub { # https://www.perlmonks.org/?node_id=11123877
my @output = @numbers[ grep $_ != $index, 0 .. $#numbers ];
join("\0", sort @output) eq join("\0", sort @expect) or die if TES
+T;
},
swap => sub {
my @output = @numbers;
$output[$index] = pop @output;
join("\0", sort @output) eq join("\0", sort @expect) or die if TES
+T;
},
});
C:\Projets\perl>perl pm_select_11123879.pm
Rate grep swap splice
grep 14287/s -- -73% -73%
swap 52519/s 268% -- -0%
splice 52549/s 268% 0% --
NB: I checked, it works fine when $index is the last element in the array as well.