From: marsberger@... (Andi Scharfstein)
Date: 2003-04-19T02:16:49+09:00
Subject: Multi-dimensional arrays

Hi,
I have created a 'Person' class that uses multi-dimensional arrays to
store information about particular interests of 'Person' objects. I
don't know by compile time how many interest groups each person is
going to have, and how many interests there are to each group. So,
until now I have used a second array (that belongs to the Person
class) to store meta-information about the interest array, in
particular, how many interests there are to each interest group.
E.g., if I had the following interest array:

Interest 1 | Interest 2 | Interest 3
Sub1       | Sub2       | Sub6
           | Sub3       | Sub7
           | Sub4       |
           | Sub5

there would be a second array of:
{ 1, 4, 2 }

I have implemented the multi-dimensional array as stated on
http://www.ir.isas.ac.jp/~masa/ruby/mdary.html, like so:

class MDArray < Array
        def [](n)
                self[n] = MDArray.new if super(n) == nil
                super(n)
        end
end

Now I wonder: is there a more efficient way to keep track of rows and
columns of this array, i.e., is there some method to extract the
number of rows a particular column has, and vice versa? Thanks a lot.

-- 
Bye: Andi S.                          mailto:nullpointer@myrealbox.com