Sort and comparison



 # Schwartzian transform
 sorted_employees = employees.sort_by {|e|e.lastname}

 # reqular sort (reverse order)
 sorted_employees = employees.sort {|a,b|b=>a}

 # find maximum an employee with highest salary
 champion = employees.max {|a,b|a.salary<=>b.salary}
 champion = employees.max_by {|x|b.salary}