Ruby: Multiply many variables with the same name

Question

I'm new to ruby. Is there any way to shorten this code? Thanks

plans.each do |plan| total = plan.landline.to_f * @landline.to_f total += plan.vpn.to_f * @vpn.to_f total += plan.other_networks.to_f * @other_networks.to_f total += plan.gprs.to_f * @gprs.to_f total += plan.sms.to_f * @sms.to_f total += plan.mms.to_f * @mms.to_f total += plan.internat_calls_zone_1.to_f * @internat_calls_zone_1.to_f total += plan.internat_calls_zone_2.to_f * @internat_calls_zone_2.to_f if total < @total @total = total @plan_new = plan end end 

Answer 1

 plans.each do |plan| total = [ :landline, :vpn, other_networks, :gprs, :sms, :mms, :internat_calls_zone_1 ].inject(0.0) do |partial_sum, term| partial_sum + plan.send(term).to_f * instance_variable_get("@#{term}").to_f end if total < @total @total = total @plan_new = plan end end 

Answer 2

I suppose you could use Enumerable#inject :

 plans.each do |plan| total = [:landline, :vpn, :other_networks, :gprs, :sms, :mms, :internat_calls_zone_1, :internat_calls_zone_2].inject(0) { |t, method| t + plan.send(method).to_f * @landline.send(method).to_f } if total < @total @total = total @plan_new = plan end end 

Answer 3

Above my head:

 plans.each do |plan| total = [ :landline, :vpn, :other_networks, :gprs, :sms, :mms, :internat_calls_zone_1, :internat_calls_zone_2 ].inject(0) {|sum,key| sum += plan.send(key).to_f * instance_variable_get(:"@#{key}").to_f sum } if total < @total @total = total @plan_new = plan end end