Question

I have trouble to understand the difference between

<%= render :partial => "book", :object => @book %>

and

<%= render :partial => "book", :collection => @books %>

and

<%= render :partial => "book", :locals => { :book => @book } %>

Can someone explain it to me ?

Answer 1

These are the same:

<%= render :partial => "book", :object => @book %>
<%= render :partial => "book", :locals => { :book => @book } %>
<%= render "book", :book => @book %>

They will render the _book.html.erb file once, and the @book object will be available in that partial as the book variable.

Here is a sweet way to abbreviate the same thing:

<%= render @book %>

This one is a little different:

<%= render :partial => "book", :collection => @books %>

It will render the _book.html.erb file once per book in @books, each in turn becoming available in that partial as the book variable.

Here is a sweet way to abbreviate the same thing:

<%= render @books %>