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!
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 }
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) %>
@book.collect(&:count).sum
试试看@books.sum(:count)
这将返回您的总和
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