Rails 3.2確定每個塊中的最後一個元素

Question

給定以下代碼，是否有方法來測試迭代是否在最後一個記錄上？我已經給出了一個我想測試的僞代碼。

@shipments.each do |shipment| 
    puts shipment.id 
    puts shipment.desc 

    unless shipment.last? #is there a way to do this line? 
    puts "that was the last shipment" 
    end 
end 

Answer 1

通過使用#last方法，你可以做這樣的事情，但我相信應該有更好的方式來實現這一目標

@shipments.each do |shipment| 
    puts shipment.id 
    puts shipment.desc 

    unless shipment == @shipments.last #is there a way to do this line? 
    puts "that was the last shipment" 
    end 
end 

Answer 2

沒有內置的方法，但是最接近這可能會是這樣的：

unless shipment == @shipments.last 

這是假定你有一組ActiveRecord的結果的工作，因爲如果@shipments是像[1, 2, 3, 2],2這樣的數組將匹配第二個元素和最後一個元素。