use strict;
use warnings;

my @arr = (9, 0, 0, 5, 3, 0, 0, 0, 2, 0, 1, 0);
print qq{@arr\n};

for my $idx ( reverse 0 .. $#arr )
{
    splice @arr, $idx, 1 unless $arr[$idx];
}
print qq{@arr\n};

##</code><code>##

9 0 0 5 3 0 0 0 2 0 1 0
9 5 3 2 1