my $dw = ' ' . join(' ', qw( ze ez ze ez zd ));
my @kw = qw( ze ez zl lz ze );

my $c = 0;
my $dw_ = $dw;
for my $kw_part (@kw) {
   my $pos = index($dw_, " $kw_part");
   next if $pos < 0;
   substr($dw_, $pos+1, 2, '');
   ++c;
}