My original post has been updated with some code to show how to do what you probably intended to do. Have a look. I think it will get you back on track. You may need to browse over one or more of the following: perlreftut, perllol, and perldsc.

I think I should explain my problem a bit more in detail: I have a hash like

my $test = (
    'a' => {
        'identifiers' => {
                                  'mrt1' => 1,
                                  'mrt2' => 1,
                                  'mrt3' => 1,
         },
    },
    'b' => {
        'identifiers' => {
                                  'mrt2' => 1,
                                  'mrt3' => 1,
                                  'mrt6' => 1,
         },
    },
    'c' => {
        'identifiers' => {
                                  'mrt1' => 1,
                                  'mrt2' => 1,
                                  'mrt3' => 1,
         },
    },
    'd' => {
        'identifiers' => {
                                  'mrt2' => 1,
                                  'mrt3' => 1,
                                  'mrt6' => 1,
         },
    },
    'sum_ab' => {
        'values' => {
                                  'a' => 1,
                                  'b' => 1,
         },
    },
    'sum_cd' => {
        'values' => {
                                  'c' => 1,
                                  'd' => 1,
         },
    },
    'sum_abcd' => {
        'values' => {
                                  'sum_ab' => 1,
                                  'sum_cd' => 1,
         },
    },
);
[download]

In case of mrt1 I do something, because a is matched. Afterwards I need to do something, because sum_ab has a in its 'values'-hash. Afterwards I have to check if some sum includes 'sum_ab' and so on...

That is the reason, why I wanted to use the nested iteration over the same hash. Perhaps I could push to some temporary variable and do the second while after the first one.

So you would benefit here from recursion:

traverse(\%my_hash);

sub traverse {
    my $hash_ref = shift;
    while ( my( $key, $value ) = each %{ $hash_ref } ) {
        if( ref $value ) {
            traverse( $value );
        } else {
            print "$key => $value\n";
        }
    }
}
[download]




Dave

In what way was my sample code inadequate?




Dave