So, your issue is that you have a number preceded by alphabetic characters, and you want to do numeric sorting on the numbers? In your sample, all your keys begin with hs. Is this guaranteed? Also, what is this %planets hash? Essentially, if you want to sort based on a substring of your key, then you will need to parse out that substring.

The easiest answer here would probably be to keep leading 0's on your keys, e.g. hs01 instead of hs1. Barring that, you could do the parsing in a named sub:

use strict;

my %planets;
my %cuantas_veces_sale;

for my $nombre (sort keysort keys %cuantas_veces_sale) {
    print "$nombre\n";
};

sub keysort {
    return $planets{$a} <=> $planets{$b} if $planets{$a} <=> $planets{
+$b};
    
    my ($num_a) = $a =~ /(\d+)/;
    my ($num_b) = $b =~ /(\d+)/;
    $num_a <=> $num_b;
}
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or possibly cache the parse in a hash ahead of time:

use strict;

my %planets;
my %cuantas_veces_sale;

my %alphas = map {$_ => /(\D+)/} keys %cuantas_veces_sale;
my %numerics = map {$_ => /(\d+)/} keys %cuantas_veces_sale;

for my $nombre (sort {   $planets{$a}  <=> $planets{$b}
                      or $alphas{$a}   cmp $alphas{$b}
                      or $numerics{$a} cmp $numerics{$b} } keys %cuant
+as_veces_sale) {
    print "$nombre\n";
};
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