Refactoring: Refactorings/Replace Loop with Collection Closure Method

Use a Ruby collection closure method instead of a loop when handling elements of a collection.

Mechanics

1. Identify the basic pattern of the loop
2. Replace the loop with the appropriate collection closure methods
3. Test

Example 1

Before

managerOffices = []
employees.each do |e|
  managerOffices << e.office if e.manager?
end

After

managerOffices = employees.select {|e| e.manager?}.collect {|e| e.office}

Example 2: Sum

Before

total = 0
employees.each {|e| total += e.salary}

After

total = employees.inject(0) {|sum, e| sum + e.salary}