ActionView::Helpers::FormOptionsHelper

options_for_select

def options_for_select(container, selected = nil)

Creates <option> elements from an array or a hash.

Changing a value updates the ERB and HTML.

container

%w[basic pro team]

[["Basic", "basic"], ["Pro", "pro"], ["Team", "team"]]

{ "Basic" => "basic", "Pro" => "pro", "Team" => "team" }

[["Basic", "basic"], ["Pro", "pro", { class: "paid" }], ["Team", "team", { disabled: true }]]

Used as the text and the value of each <option>. Accepts:

An array of strings: the text and the value are the same.
An array of [text, value] pairs, or a hash (text => value): sets the text and the value separately.
A hash as the third element of a pair: becomes HTML attributes of that <option>.

Passing nil raises NoMethodError.

selected = nil

"pro"

["pro", "team"]

{ selected: "pro", disabled: ["team"] }

Accepts:

A value: adds selected to the <option> whose value matches it.
An array of values: adds selected to each <option> whose value matches any of them.
A hash with selected and disabled keys: adds selected to each <option> whose value matches the selected key's value, and disabled to each one whose value matches the disabled key's value.

Values are compared as strings, so 2 and "2" are treated as equal.

Changes from the previous output: Added Removed Changed

Interacting with the preview updates the form submission.

Form data

name	value

Request body

Content-Type:

params