print join(',', @{ $uword{ $seen{ $key }[ 1 ] }[ 1 .. $#{ @uword{ $seen( $key ) } } ] } );
##</code><code>##

Global symbol "$seen" requires explicit package name at ./namevsfield.pl line 105.
syntax error at ./namevsfield.pl line 105, near "$seen( "
syntax error at ./namevsfield.pl line 107, near "}"
Execution of ./namevsfield.pl aborted due to compilation errors.

##</code><code>##

   foreach my $string ( @word ) {
      if ( $uword{ $string }[ 0 ] == 1 ) {
         push @{ $uword{ $string } }, $line;
         next;
      }
      $uword{ $string }[ 0 ] = 1;
      push @{ $uword{ $string } }, $line;
   }

##</code><code>##

   foreach my $string ( @data ) {   # dedupe data and sanity check.
      next if !defined ($string);   # should never be true.
      next if $seen{ $string }[ 0 ] == 1; # check %seen hash / array for dupe
      $seen{ $string }[ 0 ] = 1;    # define hash of array and assign check to it.
      $seen{ $string }[ 1 ] = $key; # add word from line to hash for reference.
   }