From: "Ara.T.Howard" <Ara.T.Howard@...>
Date: 2005-10-14T01:41:54+09:00
Subject: Re: Iterate over md Array (the Ruby way)

On Thu, 13 Oct 2005, Peter v. N. wrote:

> Hi all,
>
> Once again I disturb you for a, maybe, obvious thing
> I can't figure out.
>
> I have successfully created an md array (see older posts
> from me) thanks to the support found here.
>
> Now I would like to list all String items in the source array
> (a Text file containing numbers) and convert and place them into the 
> destination array as int objs. I know about the String#split method but this 
> recreates an array that does not match the dimensions I want
> (e.g. lines with different length).
>
> My approach is very c-ish:
>
> <code>
> # @source is a String array. If the string contains a non-convertible
> # substring, 0 is placed in destination array. @array is the destination # md 
> array created with the appropriate dimensions according to @source # (longest 
> line as vindex (-) and index as hindex (|) )
>
> for i in 0...@hindex.length
> 	for j in 0...@vindex[i].length
> 		@array[i][j] = @source[i][j].to_i.char.to_i
> 	end
> end
> </code>
>
> Is there a Ruby way to replace <code> with blocks?
>
> Thank you very much for a hint.
>
> Brgds,
> Peter

you want to be using narray i think:

   harp:~ > cat a.rb
   require 'narray'
   require 'stringio'

   sio =
     StringIO::new <<-txt
       1 0 1 0 1 0
       42 42 42

       forty-two
     txt

   na =
     NArray::int 6, 3

   j = 0
   sio.each do |line|
     row = line.strip.split(%r/\s+/).map{|s| s.to_i}
     next if row.empty?
     row.each_with_index{|n,i| na[i,j] = n}
     j += 1
   end

   p na

   3.times{|row| puts "row #{ row } => #{ na[true, row].to_a.inspect }"}

   6.times{|col| puts "col #{ col } => #{ na[col, true].to_a.inspect }"}


   harp:~ > ruby a.rb
   NArray.int(6,3):
   [ [ 1, 0, 1, 0, 1, 0 ],
     [ 42, 42, 42, 0, 0, 0 ],
     [ 0, 0, 0, 0, 0, 0 ] ]
   row 0 => [1, 0, 1, 0, 1, 0]
   row 1 => [42, 42, 42, 0, 0, 0]
   row 2 => [0, 0, 0, 0, 0, 0]
   col 0 => [1, 42, 0]
   col 1 => [0, 42, 0]
   col 2 => [1, 42, 0]
   col 3 => [0, 0, 0]
   col 4 => [1, 0, 0]
   col 5 => [0, 0, 0]


cheers.


-a
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