Ruby Rails每个循环的总价值

Question

I have a loop like this listing all count numbers like 2,44,11 etc., how do I calculate total number?

<% @book.each do |book| %>
<div><%= book.count %></div>
<% end %>

Thanks!

Answer 1

您可以使用inject来累加count并获得所有书籍的总数：

@book.inject(0) { |total, book| total + book.count }

Answer 2

You can use @books.sum , and pass it a proc which is invoked for each record, returning the number you want to add to the sum. Using Proc#to_sym gives you a very succinct syntax:

@books.sum(&:count)

---

<% @book.each do |book| %>
<div><%= book.count %></div>
<% end %>

Total books: <%= @books.sum(&:count) %>

Answer 3

@book.collect(&:count).sum

Answer 4

试试看@books.sum(:count)这将返回您的总和