kevyt has asked for the wisdom of the Perl Monks concerning the following question:

I am trying to pass 2 file handles AND 2 hashes by reference and I think I did it correctly but I dont know how to get the values once I am in the sub "catch_error". Can someone offer guidance? 
my $location_hash = get_location(\*ZIPS);
my $cat_hash = get_categories (\*SICS);

for my $city ( keys %$location_hash ) {
   printf "%s %s %s\n", $city, $location_hash->{ $city }->{ 'ST' }, $l
+ocation_hash->{ $city }->{ 'ZIP' } ;

     for my $cat ( keys %$cat_hash) {
         printf "%s %s\n", $cat, $cat_hash->{ $cat }->{ 'NUM' } ;
         .
         .
         .

         catch_error(\*LOGS, \$page, \$location_hash, \$cat_hash ); # 
+how can I pass by ref ?

         # I cant seem to delete the keys that were used.  So  so I wi
+ll set a value
         # delete ($location_hash->{ $city }->{ 'ST' }) ;   ####  Addi
+ng another post about this because I cant remove the key
           $location_hash->{ $city }->{ 'PR' } = 1;
           $cat_hash->{ $cat }->{ 'PR' } = 1;

      } # for my $cat ( keys %$cat_hash)
   } # for my $city ( keys %$location_hash ) {




sub catch_error{
   my ($fh, $str, % ) = @_;   #  confused right here!


   ### Then I will print to the log and I will print the keys
   ### and values from the hashes that I did not process.
   ### I am having a problem deleting the key so I added a key and set
+ it to 1
   ### I will create another posting for that question titled "How can
+ I delete a key from a hash".

}

[download]

Replies are listed 'Best First'.
Re: Function hash by reference.
by BrowserUk (Patriarch) on Jan 07, 2007 at 23:06 UTC

    This my $location_hash = get_location(\*ZIPS);

    and this my $cat_hash = get_categories (\*SICS); are already a hash references, so you don't need to use backslashes

    here catch_error(\*LOGS, \$page, $location_hash, $cat_hash );.

    Then, you just name the references inside the sub and use them in exactly the same way as you have in the code outside the sub. 

    sub catch_error{
   my ($fh, $str, $location_hash, $cat_hash ) = @_;   
   ...
   delete $location_hash->{'the key'};
   ...
}

    [download]
    Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
    "Science is about questioning the status quo. Questioning authority".
    In the absence of evidence, opinion is indistinguishable from prejudice.
[reply]
[d/l]
[select]
      Thank you very much!
[reply]
Re: Function hash by reference.
by shigetsu (Hermit) on Jan 07, 2007 at 23:06 UTC
    Pass $location_hash without a leading backslash, because with a leading backslash, it will generate a reference to a hash reference. Once you're in catch_error() dereference the hash as following: %$location_href.

    You should actually never pass an array or hash directly to a subroutine if you have multiple arguments being passed to it.

[reply]
[d/l]
[select]
      Thank you!
[reply]

Back to Seekers of Perl Wisdom