Delete value from Perl hash of arrays of hashes - perl

Question

I'm trying to delete values from a hash of arrays of hashes that I created with the following code:
while ((my $Genotype1, my $Fitness1) = each (%Normalisedfithash)) {
while ((my $Parent1A, my $TallyP1) = each(%P1Tallyhash)) {
my $ParentTally = 0;
my $SecondParent = {
Parent2 => $Parent1A,
Tally => $ParentTally,
};
push #{ $StoredParentshash{$Genotype1}}, $SecondParent;
I have been trying to delete values from %StoredParentshash where Tally is zero. (I have further code which updates Tally, but some are not updated and I want them removed from the hash).
I have written the following:
for my $Parent (keys %StoredParentshash) {
my $aref1 = $StoredParentshash{$Parent};
for my $hashref1 (#$aref1) {
my $Tally = $hashref1->{'Tally'};
if ($Tally == 0){
delete $hashref1->{'Tally'};
delete $hashref1->{'Parent2'};
}
}
}
This code sort of deletes the data, but when I use Data::Dumper the structure I get back looks like this:
'7412' => [
{},
{
'Tally' => 1,
'Parent2' => '2136'
},
{},
{},
{},
How can I completely remove the keys where the Tally is zero rather than being left with {}?
Thanks!

Answer 1

The code that you say has generated the data structure is faulty, as it is missing two closing braces.
You must show either your actual code with balanced { .. } or a dump of %StoredParentshash before we can help you properly.
If Tally and Parent2 are the only keys in the SecondParent hashes, then you should write something like
for my $children (values %StoredParentshash) {
#$children = grep $_->{Tally} != 0, #$children;
}

Answer 2

Your data looks like:
my %StoredParentshash = (
key1 => [
{
Tally => ...,
...
},
...
],
...
);
And you want to delete some of the array elements. Generally, I use grep for that.
#array = grep keep_condition(), #array;
Here is no exception.
for my $array (values(%StoredParentshash)) {
#$array = grep $_->{Tally}, #$array;
}
And to delete any arrays that are now empty:
for my $key (keys(%StoredParentshash)) {
delete $StoredParentshash{$key} if !#{ $StoredParentshash{$key} };
}
Or combined:
for my $key (keys(%StoredParentshash)) {
my $array = $StoredParentshash{$key};
#$array = grep $_->{Tally}, #$array;
delete $StoredParentshash{$key} if !#$array;
}