use warnings;
use strict;

my %hash = ( 1 => 'one' , 2 => 'two' , 3 => 'three' );

# Here is the one line!
my( @one ) = @hash{ my( @two ) = keys %hash };

# This line is just to demonstrate it worked.
print map { "$two[$_] => $one[$_]\n" } 0 .. $#two;