my $location_text = $locations{$ref->{'location'}};
[download]

_________
broquaint

That $ref is coming from data extracted from the database via:

        while (my $ref = $sth->fetchrow_hashref())
        {
        ...
[download]



- wil

Aha! The problem there is that the $ref lives within the lexical scope of the while loop in the bar() sub. So once the while loop exits, $ref is no longer in scope. Even if it were declared about the while loop it would fall out of scope when bar() exits. What you probably intended was something like this

sub foo {
    ...

    ## get $ref back from bar()
    my($ref, %locations) = &bar($dbh);

    ...
  
    my $location_text = $locations{$ref->{'location'}};
}

sub bar {
    ...

    my $ref;
    while ($ref = $sth->fetchrow_hashref())
    {
        my $id = $ref->{'id'};
        my $location =  $ref->{'location'};
        $locations{$id} = $location;
    }

    $sth->finish;

    ## return $ref back to caller
    return $ref, %locations;
}
[download]

However now $ref only contains the hash ref from the last iteration of the while loop, or is that the desired result?
HTH

_________
broquaint

use strict;
[download]

OK folks, here his code with my comments added:

sub foo {
    ...
########## Note that $ref does not exist(it's undef) #######

    my %locations = &bar($dbh);

## Note that $ref did not get passed back from bar ##
    ... 
  
########## $ref->{'location'} is undef, but 'use strict;'
########## here would have said: "can't use undef as hash"
    my $location_text = $locations{$ref->{'location'}};
}

sub bar {

    my $dbh = shift;

    my $sql_loc = qq|SELECT * FROM ndmw_location|; 
    my $sth = $dbh->prepare($sql_loc); 
    $sth->execute or die("...");

    my %locations;

########## Note that $ref IS my'ed here ###########

    while (my $ref = $sth->fetchrow_hashref())
    {
        my $id = $ref->{'id'};
        my $location =  $ref->{'location'};
        $locations{$id} = $location;
    }

    $sth->finish;


    return %locations;
########## Note that $ref goes away here ###########

}
[download]

If I throw all the code into one sub and not try and split it into sub-subs, it all works as expected.

Yes, it does work for him. That's beacuse $ref does not go out of scope.

Updated To make the problem/solution more clear.

If Data::Dumper shows the values coming back into %locations correctly, then I guess the problem is the key you look up ($ref->{location}). Have you checked that the key you're looking for is really in the hash? Are you perhaps being caught by invisible characters?

"The first rule of Perl club is you do not talk about Perl club."
-- Chip Salzenberg

            sub foo {

                my $location_text = $locations('id');

            }
[download]

        sub bar {

               return \%locations;

        }

        sub foo {

              $locations = &bar($dbh);

              print "The reference returned from bar is : [$locations]
+\n";


              %location_Names = %$locations;

         }
[download]

I know that this may not help you with the problem you've posted, but it is something that can become important. Then I'll nitpick one smaller thing.

Your last line of the bar() sub is return %locations, so you are copying the data structure over to the foo() sub. This might take up a few extra cycles if the hash is quite large, so you might want to consider passing by reference instead. Change that last bar() line to return \%locations;, that first line of foo() to my $locations = bar($dbh);, and then dereference $locations to get at the values. My little nitpick is getting rid of the '&' symbol that is part of your call to foo(). Nasty, nasty, nasty (:

      C:\>shutdown -s
      >> Could not shut down computer:
      >> Microsoft is logged in remotely.
    

So if you want to get the location for i.e. id=4 you have to write  $location{4}
But all in all you can do it a bit more easier I think:

use DBI;
my %location = map {  $_->[0] => $_->[1] } @{$dbh->selectall_arrayref(
+'select id, location from ndmw_location')};
[download]

Hope this helps ?