For what it's worth.. and I don't know if it's "too clever for my own good", here's something I've built to assist in the creation of the '2-way' structures.

...and all I'll need to do as time goes on is add to the conditional where there's a '@B_list = ' in the code...

Just for the curious :) ... 

# --------------------------------------------------------------------
+--------------
#  Build_Joined_Hashes - Build hashes to assist '2-way' queries
#  
#  Description:
#    Create hashes where B -> (A1, A2, ...) and A -> (B1, B2, ...)
#    That is: 
#       1.  given B, get a list of A's that refer to B
#       2.  given A, get a list of B's that refer to A
#
#  Uses Globals:
#
#  Notes:
#    - VP DSK hash: 2324(LX INT) -> VAR2=36!550!0!:VAR4=36!554!0!:VAR6
+=36!551!0!
#    - TC DSK hash: 9705(LX TC) -> 11,13-JAN-2014:13-JAN-2014
# --------------------------------------------------------------------
+--------------

sub Build_Joined_Hashes
{
   my ($input_hash_ref, $type, $A_B_hash_ref, $B_A_hash_ref) = @_;

   my ($buf, $A_item, $input_field, $B_item, $key);
   
   my (@input_item, @B_list);
   
   my (%tmp_hash);
   
   
   %tmp_hash      = ();  # hash: A:B -> (count)

   %$A_B_hash_ref = ();  # List of Bs that are used in As
   %$B_A_hash_ref = ();  # List of As that are used in Bs
   
   foreach $A_item (keys %$input_hash_ref) {           # For each 'A' 
+item...
      $buf = $$input_hash_ref{$A_item};                # ..get 'B usag
+e list' record
      @input_item = split(/:/, $buf);                  # Get each 'B u
+sage' item
      
      foreach $input_field (@input_item) {             # For each 'B u
+sage' item...
      
         if ($type eq "VAR") {                         # Get list of '
+B' instances...
            @B_list = ($input_field =~                 # ... when VAR.
+..
                          /([0-9]+)!([0-9]+)!$/); 
            
         } elsif ($type eq "TC") {
            @B_list = ($input_field =~                 # ... when TC..
+.
                          /^([0-9]+),/);
         
         }         
      
         foreach $B_item (@B_list) {                   # Each 'B' inst
+ance...
            next if ($B_item == 0);                    # Skip '0' item
+s
            $key = $A_item . ":" . $B_item;            # Make composit
+e key: A:B -> (count)
            $tmp_hash{$key}++;   
         }
      }
   }
   
   foreach $key ( sort keys %tmp_hash ) {              # For every 'B 
+usage in A' instance...
      ($A_item, $B_item) = split(/:/, $key);
   
      push( @{ $$A_B_hash_ref{$B_item} }, $A_item );   # Build list of
+ B -> (A1, A2, ...)
      push( @{ $$B_A_hash_ref{$A_item} }, $B_item );   # ...       and
+ A -> (B1, B2, ...)
   }

   return;

} # end Build_Joined_Hashes

[download]

Perhaps it would be a better approach(?) to simply do things using DBD::CSV and treat everything as a database(!) and use SQL or sumfin'...

In reply to Re: How to Check Hashes for Missing Items when Keys can be Values and vice versa by ozboomer
in thread How to Check Hashes for Missing Items when Keys can be Values and vice versa by ozboomer

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