my @clean = grep { defined } @data;

##</code><code>##

my @clean = grep { $_ ne '' } @data;

##</code><code>##

#!/usr/bin/perl -w
use strict;

my @data= (1, 2, 3, 'a', undef, 4, '', 5, 'b');

my @clean = grep { defined && $_ ne ''  } @data;

print join ",", @clean;
print "\n";