How would I check if a value is found in an array of values

Question

I want to perform an if condition where, if linkedpub.LPU_ID is found in an array of values(@associated_linked_pub), do some action.

I tried the following but the syntax is not correct.

Any suggestion is most welcomed..Thanks a lot

<% for linkedpub in Linkedpub.find(:all) %>
   <% if linkedpub.LPU_ID IN @associated_linked_pub  %>
       # do action
   <%end%>
<%end%>

Answer 1

You can use Array#include?

So...

if @associated_linked_pub.include? linkedpub.LPU_ID
  ...

Edit:

If @associated_linked_pub is a list of ActiveRecord objects then try this instead:

if @associated_linked_pub.map{|a| a.id}.include? linkedpub.LPU_ID
  ...

Edit:

Looking at your question in more detail, it looks like what you are doing is VERY inefficient and unscalable. Instead you could do...

For Rails 3.0:

Linkedpub.where(:id => @associated_linked_pub)

For Rails 2.x:

LinkedPub.find(:all, :conditions => { :id => @associated_linked_pub })

Rails will automatically create a SQL IN query such as:

SELECT * FROM linkedpubs WHERE id IN (34, 6, 2, 67, 8)

Answer 2

linkedpub.LPU_ID.in?(@associated_linked_pub.collect(&:id))

Using in? in these cases has always felt more natural to me.