How to loop through ActiveRecord values in Rails?

Question

I have the following columns in my table:

value1 value2 value3 value4 value5

I want to be able to loop through them like this:

<% for i in 1..5 %>
  <div><%= user."value#{i}"</div>
<% end %>

Of course this code doesn't work, so how can I get the value from an ActiveRecord object with a string?

Jaime Bellmyer · Accepted Answer · 2010-10-29 16:00:29Z

7

Wow, unless you really have a bad naming convention for your attributes, the send method is only going to get you halfway there. Are your attribute names really numbered sequentially?

Here's how to loop through your attributes regardless of their names:

<% user.attributes.each do |name, value| %>
  <div>
    <%= name %>: <%= value %>
  </div>
<% end %>

I hope this helps, let me know if you have any questions.

answered Oct 29, 2010 at 16:00

Jaime Bellmyer

23.4k7 gold badges55 silver badges51 bronze badges

Sign up to request clarification or add additional context in comments.

3 Comments

Mike Trpcic Over a year ago

The problem with this is that it will do all attributes. It's entirely possible that his Rails application is interacting with some horribly formatted/named legacy database, and there are 5 fields named "contact1", "contact2" and so on.

Jaime Bellmyer Over a year ago

This will certainly loop through all attributes, as advertised. If you want to weed some out, you can easily do that with the select method. I just didn't want him feeling like he has to name fields that way to be able to loop through them.

Alex Over a year ago

Like Mike said, there's some horrible stuff in the database that literally looks like this: value1, value2, value3, value4, value5. So yes, they are numbered sequentially. Good point though.

Mike Trpcic · Accepted Answer · 2010-10-29 14:43:53Z

4

You can use the send method to send a method name to any object as a string. The example below is what you're looking for.

<% for i in 1..5 %>
  <div><%= user.send("value#{i}") %></div>
<% end %>

answered Oct 29, 2010 at 14:43

Mike Trpcic

25.7k8 gold badges80 silver badges117 bronze badges

Comments

Kevin Sylvestre · Accepted Answer · 2010-10-29 14:41:45Z

2

Try using send (see Ruby documentation).

answered Oct 29, 2010 at 14:41

Kevin Sylvestre

38.2k33 gold badges159 silver badges235 bronze badges

1 Comment

Kevin Sylvestre Over a year ago

No problem. Yes, Ruby is amazing! :)

Collectives™ on Stack Overflow

How to loop through ActiveRecord values in Rails?

3 Answers 3

3 Comments

Comments

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

3 Comments

Comments

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related