Re: recursive hash layer removal question

My inital thoughts: (might update it later)

Change your foreach loop into this:

if (ref $refToHash->{$a} eq 'HASH') 
{
    foreach $b (keys %{$refToHash->{$a}})
    {
        $refToHash->{$b} = $refToHash->{$a}->{$b};
    }
}
delete($refToHash->{$a});
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The problems with your current code:

You are dereferencing a hash element without checking if the element is a hash referene (use the ref-function)
You are deleting the original element ($refToHash->{$a}) inside the foreach loop, this is not a good idea...

Note, if you remove the last layer with this code then the previous layer will point to empty hash reference... is that what you want? (add an else statement to the 'if (ref ..)' if it isn't

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Re^2: recursive hash layer removal question by wertert (Sexton) on May 10, 2005 at 17:38 UTC
Thanks for the fast reply. I'm sorry I normally check for hash reference. Can't understand why I didn't here i must have recursion brain ache. Example is the printTree function removed from the original post. `sub printTree { my($a)=shift; my(@l); foreach $b (sort keys %{$a}) { if(ref($a->{$b}) eq 'HASH') { $l[$depth]=$b; print "@l\n"; $depth++; printTree($a->{$b}); $depth--; } else { $l[$depth]=$b; print "@l\n"; } } }` [download]	[reply] [d/l]

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Re^2: recursive hash layer removal question
by wertert (Sexton) on May 10, 2005 at 17:38 UTC

sub printTree
{
    my($a)=shift;
    my(@l);
    
    foreach $b (sort keys %{$a})
    {
        if(ref($a->{$b}) eq 'HASH')        
        {
            $l[$depth]=$b;
            print "@l\n";
            $depth++;
            printTree($a->{$b});
            $depth--;
        }
        else
        {
            $l[$depth]=$b;
            print "@l\n";
        }
    }
}
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