You want grep (to remove rows), map (to transform rows) or List::MoreUtils's apply (to transform rows).

When using grep or map, don't change $_ unless you want to change the original array.

apply is similar to map, but you can safely modify $_. The downside to using apply is that you're limited to 1:1 transformations (whereas map is extremely flexible).

use List::MoreUtils qw( apply );

my @orig    = qw( Just another Perl hacker );
my @grepped = grep  { /^[A-Z]/      } @orig;
my @mapped  = map   { uc            } @orig;
my @applied = apply { s/[aiueo]//ig } @orig;

print("@orig\n");     # Just another Perl hacker
print("@grepped\n");  # Just Perl
print("@mapped\n");   # JUST ANOTHER PERL HACKER
print("@applied\n");  # Jst nthr Prl hckr
[download]

List::MoreUtils can easily be installed if you're using ActivePerl. Just type by ppm install List-MoreUtils at the prompt