use Modern::Perl;
use Data::Dumper;

my @array = qw/1 A 2 B 3 C 4 D 5 E/;
my $i = 0;

say 'Before:';
say Dumper \@array;

@array = grep !($i++ % 2), @array;

say 'After:';
say Dumper \@array;