From: Mark Wilson <mwilson13@...>
Date: 2003-02-20T03:09:30+09:00
Subject: Re: 2d array?


On Wednesday, February 19, 2003, at 10:28 AM, Armin Roehrl wrote:

>> Sorry, new to ruby.  Does ruby have a 2d array?  If so, where could I
>> find the documentation?
> One possibility is to put Arrays in Arrays. This way you can
> create n-d Arrays. Here is a 2-d array.
>
> irb(main):001:0> t=[[1,2,3],[4,5,6],[7,8,9]]
> [[1, 2, 3], [4, 5, 6], [7, 8, 9]]
> irb(main):002:0> t[0][1]
> 2
> irb(main):003:0>
>
> Maybe you also want to use at matrix, which by
> definition is a 2d array.
>
> Good luck,
> 	-A.
> ----------------------------------------
> Armin Roehrl, http://www.approximity.com

I think Armin's reference to 'at matrix' is a reference to matrix.rb, 
which is a Matrix class that is part of the Ruby standard distribution. 
matrix.rb is a port of smalltalk's matrix class and includes finding 
methods (rank, determinant, etc.) and transformation methods  (such as 
transposition).

Mark Slagell's book, "Teach Yourself Ruby", includes a chapter that 
walks through creating an integer matrix with a number of useful 
methods.

Also, a 2d array (a matrix) can be of any dimension in mathematical 
terms, represented by a 'table' of ordered rows and columns.