How to find if an array has a value not found in list-CodePudding

I have array @hon_data. If any elements of the array are one of a known list of values, I return zero.

for my $hon_field (@hon_data) {
    if($hon_field ne 'B' and $hon_field ne 'S' and $hon_field ne 'G' and 
      $hon_field ne 'D' and $hon_field ne 'L') {
      return 0;
    }
  }

The number of values to check is growing, so this approach is getting complicated to manage. Is there a way to do this with the values in an array?

my @results =("B","G","S","D","N","L");
my @results2 = ("A","G","S","D","N","L");

sub uniq {
    my %seen;
    grep { !$seen{$_}   } @_;
}

my @unique = uniq(@results, @results2);

In result2 A is unique value and it should return A only But this code is not working.

CodePudding user response：

You're asking how to replace the hardcoded loop with a dynamic one. The following is one way this could be done:

for my $hon_field ( @hon_data ) {
   for my $ok (qw( B S G D L )) {
      if ( $hon_field ne $ok ) {
         return 0;
      }
   }
}

That is a lot better. But if the elements are strings, the inner loop can be replaced with a hash lookup.

my %ok = map { $_ => 1 } qw( B S G D L );

for my $hon_field ( @hon_data ) {
   if ( !$ok{ $hon_field } ) {
      return 0;
   }
}

This can also be written as follows:

use List::Util qw( any );

my %ok = map { $_ => 1 } qw( B S G D L );

return 0 if any { !$ok{$_} } @hon_data;

A similar approach can be used to find the difference of sets.

my %ok = map { $_ => 1 } qw( B S G D L );;

my @diff = grep { !$ok{ $_ } } @hon_data;    # diff = hon_data - { B, S, G, D, L }