From: James Coglan <jcoglan@...>
Date: 2009-04-13T20:46:03+09:00
Subject: Re: single to multi dimension array conversion

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2009/4/13 James Coglan <jcoglan@googlemail.com>

> 2009/4/13 Ashikali Ashikali <ashikali.m@gmail.com>
>
> > Ashikali Ashikali wrote:
> > > Can any one tell me converting single to multi dimension array
> > > conversion
> > >
> > > For example ,
> > >      a = [ 1,2,3,4,5,6,7,8,9,10 ]
> > >      a.<methodName>( 2,3 )
> > >
> > >       Output,
> > >
> > >
> > >
> > > here ,
> > >      2 means dimension No
> > >      3 means elements in each dimension
> >
> >
> > In above example output should be ,
> >   a = [ [1,2,3],[4,5,6],[7,8,9] , [ 10 ] ]
>
>
> That has more than three elements along the outermost direction. It
> represents the matrix:
>
> 1  2  3
> 4  5  6
> 7  8  9
> 10
>

Although, here's one possible and slightly more general solution:

class Array
  def multidim(*sizes)
    split = sizes.inject { |a,b| a * b }
    return self unless split
    result = []
    each_slice(split) { |slice| result << slice.multidim(*sizes[1..-1]) }
    result
  end
end

With this, you specify how many you want in each dimension, so:

[1,2,3,4,5,6,7,8,9,10].multidim(3)
#=> [[1,2,3],[4,5,6],[7,8,9],[10]]

It works from the outside in, so for higher dimensions it works like this:

[1,2,3,4,5,6,7,8,9,10].multidim(3,2)
#=> [ [ [1, 2],
        [3, 4],
        [5, 6]
      ],
      [ [7, 8],
        [9, 10]
    ] ]

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