grouped_options_for_select

Returns a string of <option> tags, like options_for_select, but wraps them with <optgroup> tags:

Possible output:

Parameters:

• grouped_options - Accepts a nested array or hash of strings. The first value serves as the <optgroup> label while the second value must be an array of options. The second value can be a nested array of text-value pairs. See options_for_select for more info.

  1	Ex. ["North America",[["United States","US"],["Canada","CA"]]]

• selected_key - A value equal to the value attribute for one of the <option> tags, which will have the selected attribute set. Note: It is possible for this value to match multiple options as you might have the same option in multiple groups. Each will then get selected="selected".

Options:

• :prompt - set to true or a prompt string. When the select element doesn't have a value yet, this prepends an option with a generic prompt - âPlease selectâ - or the given prompt string.

• :divider - the divider for the options groups.

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  grouped_options = [   [['United States','US'], 'Canada'],   ['Denmark','Germany','France'] ] grouped_options_for_select(grouped_options, nil, divider: '---------')

  Possible output:

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  <optgroup label="---------">   <option value="US">United States</option>   <option value="Canada">Canada</option> </optgroup> <optgroup label="---------">   <option value="Denmark">Denmark</option>   <option value="Germany">Germany</option>   <option value="France">France</option> </optgroup>

Note: Only the <optgroup> and <option> tags are returned, so you still have to wrap the output in an appropriate <select> tag.