Question

I have just read the Rails API definition for option_from_collection_for_select.

 Returns a string of option tags that have been compiled by iterating over the collection   and assigning the result of a call to the value_method as the option value and the text_method as the option text

Now I am very new to rails so was wondering if someone could break this down into smaller chunks and explain what is happening, dumb it down if you will, the explanation is very high level (well for me at the moment)

Thank you

Answer 1

Using the example from the Ruby on Rails API, let’s assume you have a Person model that has an id attribute and a name attribute.

Say you have a form that creates a new project and assigns it to a person. Maybe you want to have a drop down select for what person you’re assigning this project to. You could use options_from_collection_for_select for something like this.

<%= f.label :person, "Assigned Person" %>
<%= f.select(:person, options_from_collection_for_select(@people, "id", "name") )

(f by the way would be referring to the @project variable for our example form here.)

What this would do is create an option in your select drop-down for each person contained in the instance variable @people. Each of the <option> tags would have the id of that person assigned to its value attribute, and the text for that option would be the person‘s name.

So if your @people variable contained [#<Person id: 1, name: "Brock Sampson">, #<Person id: 2, name: "Byron Orpheus">], you would get HTML output like this:

<label for="project_person">Assigned person"</label>
<select id="project_person" name="project[person]">
  <option value="1">Brock Sampson</option>
  <option value="2">Byron Orpheus</option>
</select>

Does that make more sense?