use strict;
use warnings;

my @array = (1, 2, undef, 4, 5, 0, undef, 8, 9);

print join (' ', grep $_, @array)."\n";
print join (' ', grep { defined } @array)."\n";

##</code><code>##

1 2 4 5 8 9
1 2 4 5 0 8 9