#!/usr/bin/perl -l
use strict;
use warnings;

my %hash = (
    foo => 1,
    whatever    => { rank => 11 },
    you         => { rank => 2  },
    want        => { rank => 7  },
);

my @arr = grep { $_ ne 'foo' } keys %hash;

my @sorted = sort { $hash{$a}->{rank} <=> $hash{$b}->{rank} } @arr; 

print "@arr";
print "@sorted";