Question

If I have a hash:

%hash = ("Dog",1,"Cat",2,"Mouse",3,"Fly",4);

How can I extract the first X elements of this hash. For example if I want the first 3 elements, %newhash would contain (“Dog”,1,”Cat”,2,”Mouse”,3).

I’m working with large hashes (~ 8000 keys).

Answer 1

“first X elements of this hash” doesn’t mean anything. First three elements in order by numeric value?

my %hash = ( 'Dog' => 1, 'Cat' => 2, 'Mouse' => 3, 'Fly' => 4 );
my @hashkeys = sort { $hash{$a} <=> $hash{$b} } keys %hash;
splice(@hashkeys, 3);

my %newhash;
@newhash{@hashkeys} = @hash{@hashkeys};