Rails - grouped_options_for_select

Question

I am having some difficulty populating a select box in Rails with option groups using `grouped_options_for_select`. I currently have 3 instance variables that I would like to add to one entire grouped array for the grouped select box. For example, I have: ``` @fruits (which contains the object(s)) --- !ruby/object:Fruits attributes: id: 2 name: Banana @veggies (which contains the object(s)) --- !ruby/object:Veggies attributes: id: 23 name: Celery --- !ruby/object:Veggies attributes: id: 24 name: Carrots @junk_food (which contains the object(s)) --- !ruby/object:Junk attributes: id: 11 name: Snickers --- !ruby/object:Junk attributes: id: 12 name: Ice Cream ``` My question is: How do I take these 3 instance variables and turn them into a grouped select, like: ```

Accepted Answer

The `grouped_options_for_select` method indeed is the correct one. Since you haven't provided code, this should result in the grouped options you want:

```
grouped_options_for_select [['Fruits',  @fruits.collect {|v| [ v.name, v.id ] }],
                            ['Veggies', @veggies.collect {|v| [ v.name, v.id ] }],
                            ['Junk',    @junk_food.collect {|v| [ v.name, v.id ] }]]
```

Which can be used to create the dropdown:

```
select_tag 'Food', grouped_options_for_select(...)
```

or with form_helper:

```
f.select :food_attribute, grouped_options_for_select(...)
```

Rails - grouped_options_for_select

Solution

Problem