Global symbol "@keys" requires explicit package name ...
Execution ... aborted due to compilation errors.

##</code><code>##

$ perl -e '
    my $x = "MIR200B miRNA";
    my %h;
    my ($k, $v) = split /:/, $x;
    $h{$k} = $v;
    use Data::Dumper;
    print Dumper(\%h);
'
$VAR1 = {
          'MIR200B miRNA' => undef
        };

##</code><code>##

#!/usr/bin/env perl

use strict;
use warnings;

my %data;

while (<DATA>) {
    next if $. == 1;
    chomp;
    next unless length;
    my ($k, $v) = split;
    $data{$k} = $v;
}

# To test result
use Data::Dumper;
print "*** Hash ***\n";
print Dumper(\%data);
print "*** Keys ***\n";
print "$_\n" for keys %data;
print "*** Values ***\n";
print "$_\n" for values %data;

__DATA__
GeneName    GeneType

APOL4   protein_coding

CYP2C8  protein_coding

NAALADL2    protein_coding

NANOS3  protein_coding

C20orf204   protein_coding

MIR429  miRNA

MIR200A miRNA

MIR200B miRNA

##</code><code>##

*** Hash ***
$VAR1 = {
          'NANOS3' => 'protein_coding',
          'C20orf204' => 'protein_coding',
          'APOL4' => 'protein_coding',
          'MIR429' => 'miRNA',
          'NAALADL2' => 'protein_coding',
          'MIR200B' => 'miRNA',
          'MIR200A' => 'miRNA',
          'CYP2C8' => 'protein_coding'
        };
*** Keys ***
NANOS3
C20orf204
APOL4
MIR429
NAALADL2
MIR200B
MIR200A
CYP2C8
*** Values ***
protein_coding
protein_coding
protein_coding
miRNA
protein_coding
miRNA
miRNA
protein_coding