Hi,

I basically have a function that I would like to call recursively to delete certain values from a hash. These values are interdependent, so if I need to delete a certain value, I also want to delete all other values that depend on that one.

For example, I have something like

my %hash = ( 'one' => 1, 'two' => 2, 'three' => 3, 'four' => 4, 'five'
+ => 5);
my %dependencies =( 'one' => [], 'two' => [], 'three' => ['four'], 'fo
+ur' => ['one','two'], 'five' => ['three']);
[download]

so if I need to delete 'one' from the list, I must also then also delete the keys 'three' and 'four' from the hash.

So my function looks something like

sub my_del($){
while (my $key = each (%hash)){
print "KEY = $key\n";

foreach (@{ $dependencies{$key} }){
        if( $_ eq $_[0]){
                print"Going to call sub for $key\n";
                my_del($key);
}
}
print"\n";
}
delete $hash{$_[0]};
print "Deleting $_[0]\n";
}


my_del('one');
[download]

The resulting output is

KEY = three

KEY = five

KEY = one

KEY = two

KEY = four
Going to call sub for four
Deleting four

KEY = three

KEY = five

KEY = one

KEY = two

Deleting one
[download]

It is as if the "each" somehow is like a "global" in that when I call the function recursively, it remembers at which value it was at and continues from there.

Note that sometimes it will work depending of the ordering if the hash. eg, it works fine when I used

my %dependencies =( 'one' => [], 'two' => [], 'three' => ['one'], 'fou
+r' => ['three','two'], 'five' => ['three']);
[download]

I got

KEY = three
Going to call sub for three
KEY = five
Going to call sub for five
KEY = one

KEY = two

KEY = four

Deleting five

KEY = three

KEY = one

KEY = two

KEY = four
Going to call sub for four
Deleting four

KEY = three

KEY = one

KEY = two

Deleting three

KEY = one

KEY = two

Deleting one
[download]

Any help would be gratefully appreciated. I am from a "C" background and I had thought it would work like I'd have expected to in "C". i.e. when each recursive call is made, local variables are created and everything starts again for that function. Thanks

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