Rails Partials - can't perform a collect on a symbol

Question

I'm trying to render a partial, and want to use symbols to pass in the data:

<%= render 'form', :locals => { :course => @course, :categories => @categories } %>

In my partial though, I can't perform a collect on the :categories symbol, I get this error:

    undefined method `collect' for :categories:Symbol

    Extracted source (around line #9):

<%= f.select :category_id, :categories.collect{ |c| [c.name, c.id]}, {}, :style => 'font-size:1em;width:250px;'  %>

Can you not use symbols this way?

Answer 1

You are calling collect on :categories, instead of categories.

<%= f.select :category_id, categories.collect { |c| [c.name, c.id]}, {}, :style => 'font-size:1em;width:250px;'  %>

instead of

<%= f.select :category_id, :categories.collect{ |c| [c.name, c.id]}, {}, :style => 'font-size:1em;width:250px;'  %>

Moreover, you are mixing the two syntax to call render. It should be either

<%= render partial: 'form', :locals => { :course => @course, :categories => @categories } %>

or

<%= render 'form', :course => @course, :categories => @categories %>

Answer 2

Don't reference the symbols in your partial, reference the instance of them.

<%= f.select :category_id, categories.collect{ |c| [c.name, c.id]}, {}, :style => 'font-size:1em;width:250px;'  %>