Iterate over hash of arrays from function - perl

Question

I have an input file:
id_1 10 15 20:a:4:c
id_2 1 5 2:2:5:c
id_3 0.4 3 12:1:4:1
id_4 18 2 9:1:0/0:1
id_5 a b c:a:foo:2
I have many files of this type that I want to parse in different programs, so I want to make a function that returns a hash with easily accessible.
I've not written a function like this before, and I'm not sure how to properly access the returned hashes. Here's what I've got so far:
Library_SO.pm
#!/urs/bin/perl
package Library_SO;
use strict;
use warnings;
sub tum_norm_gt {
my $file = shift;
open my $in, '<', $file or die $!;
my %SVs;
my %info;
while(<$in>){
chomp;
my ($id, $start, $stop, $score) = split;
my #vals = (split)[1..2];
my #score_fields = split(/:/, $score);
$SVs{$id} = [ $start, $stop, $score ];
push #{$info{$id}}, #score_fields ;
}
return (\%SVs, \%info);
}
1;
And my main script:
get_vals.pl
#!/urs/bin/perl
use Library_SO;
use strict;
use warnings;
use feature qw/ say /;
use Data::Dumper;
my $file = shift or die $!;
my ($SVs, $info) = Library_SO::tum_norm_gt($file);
print Dumper \%$SVs;
print Dumper \%$info;
# for (keys %$SVs){
# say;
# my #vals = #{$SVs{$_}}; <- line 20
# }
I call this with:
perl get_vals.pl test_in.txt
The Dumper output is what I was hoping for, but when I try to iterate over the returned hash(?) and access the values (e.g. as in the commented out section) I get:
Global symbol "%SVs" requires explicit package name at get_vals.pl line 20.
Execution of get_vals.pl aborted due to compilation errors.
Have I got this totally upside down?

Answer 1

Your library function returns two hashrefs. If you now want to access the values you'll have to dereference the hashref:
my ($SVs, $info) = Library_SO::tum_norm_gt($file);
#print Dumper \%$SVs;
# Easier and better readable:
print Dumper $SVs ;
#print Dumper \%$info;
# Easier and better readable:
print Dumper $info ;
for (keys %{ $SVs } ){ # Better visual derefencing
say;
my #vals = #{$SVs->{$_}}; # it is not $SVs{..} but $SVs->{...}
}