Get value from hash of hashes - perl

Question

I would like to get value from hash of hashes but i do not. My code is :
sub test {
my $filename = $_[0];
open INFILE, ${filename} or die $!;
my %hashCount;
my #firstline = split('\t',<INFILE>);
shift(#firstline);
while (my $line = <INFILE>)
{
my %temp;
chomp($line);
my #line = split('\t', $line);
foreach my $cpt (1..$#line) {
$temp{$firstline[$cpt-1]}=$line[$cpt];
}
$hashCount{$line[0]}={%temp};
}
return %hashCount;
}
sub get_hash_of_hash {
my $h = shift;
foreach my $key (keys %$h) {
if( ref $h->{$key}) {
get_hash_of_hash( $h->{$key} );
}
else {
say $h->{$key};
}
}
}
And when i display my hash :
$VAR10679 = 'M00967_43_1106_2493_14707';
$VAR10680 = {
'A' => '1',
'B' => '0',
'C' => '1',
'D' => '0',
'E' => '0'
};
My first function return my hash of hashes and i get my specific value with the second function.
So I want to get value like that :
my %hashTest = test("FILE.txt");
get_hash_of_hash(%hashTest,"M00967_43_1106_2493_14707","A")
//return value '1'

Answer 1

You can either access nested elements like
$hash{keyA}{keyB}
or we can write a function that walks the data structure, like
sub walk {
my ($hashref, #keys) = #_;
my $pointer = $hashref;
for my $key (#keys) {
if (exists $pointer->{$key}) {
$pointer = $pointer->{$key};
} else {
die "No value at ", join "->", #keys;
}
}
return $pointer;
}
which can be used like
my %hash = (
'M00967_43_1106_2493_14707' => {
'A' => '1',
'B' => '0',
'C' => '1',
'D' => '0',
'E' => '0'
},
);
say walk(\%hash, 'M00967_43_1106_2493_14707', 'A');
Note: When using Data::Dumper, pass references to the Dump function:
print Dump \%hash; # not print Dump %hash
This is neccessary to show the correct data structure.

Answer 2

Your hash holds references to hashes.
You can access them like this:
$hashTest{'M00967_43_1106_2493_14707'}{'A'};
See perlref for more info

Answer 3

Use this subroutine..
sub get_hash_of_hash {
my $h = shift;
foreach my $key (keys %$h) {
if( ref $h->{$key}) {
get_hash_of_hash( $h->{$key} );
}
else {
print $h->{$key};
}
}
}