From: Brian Adkins <lojicdotcom@...>
Date: 2008-11-02T01:43:57+09:00
Subject: Re: n-dimensional array in Ruby

Michael Guterl <mguterl@gmail.com> writes:

> On Fri, Oct 31, 2008 at 8:09 PM, Christian <stadeschuldt@googlemail.com> wrote:
>> Hi,
>>
>> i have a little Java problem, I want to solve using Ruby. Therefor I
>> need an n-dimensional array. In Java it looks like this:
>>
>> double dArray[][][] = new double[x.length()+1][y.length()+1][x.length()
>> +y.length()+3];
>> dArray[0][0][0] = 0;
>> dArray[0][0][1] = POSITIVE_INFINITY;
>>
>> Further values will be computed through loops and written into the
>> array.
>>
>> How do I initialize such an array in Ruby?
>>
> Infinity = 1.0/0

~$ irb
irb(main):001:0> X = 7
=> 7
irb(main):002:0> Infinity = 1.0/0
=> Infinity
irb(main):003:0> 0 / Infinity
=> 0.0
irb(main):004:0> Infinity * Infinity
=> Infinity
irb(main):005:0> Beyond = Infinity
=> Infinity
irb(main):006:0> 2 * Infinity and Beyond
=> Infinity
irb(main):007:0> Infinity.infinite?
=> 1

Cool - I just learned about Infinity in Ruby. Hey Dave Thomas, maybe
you could add a bit about Infinity in the next relase of Programming
Ruby or Programming Ruby 1.9

>
> a = [[],[],[]]
> a[0][0][0] = 0
> a[0][0][1] = Infinity
>
> The arrays will grow to whatever size you need them to.
>
> HTH,
> Michael Guterl