From: Lars Haugseth <ruby-talk@...>
Date: 2012-04-11T20:16:33+09:00
Subject: Re: less absolutely horrible way to make sure array 1 only contains elements from array 2?

On 04/11/2012 03:44 AM, ruby ismyname wrote:
> I need to make sure that myselections only contains elements from
> choices, includes? doesn't work because it allows for partial matches.
> This works but it looks absolutely horrible.
>

require 'set'

valid_choices = Set[:a, :b, :c, :d, :e, :f]

good = Set[:a, :b, :d, :e]
good.subset? choices
  => true

bad = Set[:c, :f, :x, :y]
bad.subset? choices
  => false

Note: you can use Array#to_set to convert an array to a set.

-- 
Lars Haugseth