Ruby Rails total value of loop each

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!

user229044 · Accepted Answer · 2014-01-10 07:16:24Z

3

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) %>

edited Jan 10, 2014 at 7:16

answered Jan 10, 2014 at 7:09

user229044♦

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2 Comments

test Over a year ago

sorry im newb where should i put this ? inside of the loop ?

user229044 Over a year ago

No, just wherever you want to get the sum of counts. See update.

vee · Accepted Answer · 2014-01-10 07:03:45Z

3

You can use inject to add up the counts and get the total count of all the books:

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

answered Jan 10, 2014 at 7:03

vee

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Comments

arun15thmay · Accepted Answer · 2014-01-10 07:04:16Z

2

@book.collect(&:count).sum

answered Jan 10, 2014 at 7:04

arun15thmay

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Comments

Nitin Jain · Accepted Answer · 2014-01-10 07:11:43Z

1

try it out @books.sum(:count) this will return you sum

answered Jan 10, 2014 at 7:11

Nitin Jain

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