while (my $key = shift @keys and my $value = shift @values) {
  $hash{$key} = $value;
}

##</code><code>##

while (defined (my $key = shift @keys) and defined(my $value = shift @values)) {
  $hash{$key} = $value;
}

##</code><code>##

while (@keys and @values) {
  $hash{shift @keys} = shift @values;
}