From: Ammar Ali <ammarabuali@...>
Date: 2012-04-11T13:09:44+09:00
Subject: Re: less absolutely horrible way to make sure array 1 only contains elements from array 2?

On Wed, Apr 11, 2012 at 4:44 AM, ruby ismyname <lists@ruby-forum.com> 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.

How about using array difference using the #- method?

>> choices = [1, 2, 3, 4]
=> [1, 2, 3, 4]
>> selection_good = [2, 4]
=> [2, 4]
>> selection_good - choices
=> []
>> selection_bad = [2, 6]
=> [2, 6]
>> selection_bad - choices
=> [6]

HTH,
Ammar