From: Jean-Julien Fleck <jeanjulien.fleck@...>
Date: 2010-08-21T23:23:21+09:00
Subject: Re: A small problem for arrays

2010/8/21 Unc88 Unc88 <unc88@mail.ru>:
> I have 2 array. ar_1, ar_2
> How can we, on the basis of existing arrays to create an array ar_3, of
> all the elements that are ar_1 and are not included in ar_2.

Just make the difference between the two arrays:

>> a1 = (1..10).to_a
=> [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
>> a2 = (4..7).to_a
=> [4, 5, 6, 7]
>> a1 - a2
=> [1, 2, 3, 8, 9, 10]
>> a2 - a1
=> []

Cheers,

-- 
JJ Fleck
PCSI1 Lycée Kléber