配列の添え字が偶数の要素だけ取り出す

$array[0], $array[2], $array[4]...

my @array = 0 .. 99;
my @even = even_elemnt(@array);

sub even_element {
  my $i = 0;
  return grep ++$i % 2, @_;
}

Test.

use Test::More;
my @array = 0 .. 99;
my @even = even_element(@array);

for my $elm (@even) {
  ok !($elm % 2);
}

done_testing;