Two Dimensional Array

ruby-talk
1

class Tda

  def initialize(width=0, height=0)
    if((width==0) && width<height)
      raise NotImplementedError,
      "\(#{width}\) width Tda cannot have a height."
    else
      @tda = Array.new(width).map!{ Array.new(height) }
    end
  end

  def width?
    return @tda.size
  end

  def height?
    if(width?>0)
      return @tda[0].size
    else
      return nil
    end
  end

  #--Returns the dimensional size (x x y) as a string
  def size
    w=@tda.size

    if(width?>0)
      h = @tda[0].size
    else
      h = 0
    end

    return "#{w}x#{h}"
  end

  #--Returns true if both Tda's have equal widths and heights
  def eql_size?(tda)
    bool=false

    lh=size.split('x')
    rh=tda.size.split('x')

    if(lh[0]==rh[0])
      bool=true
    end

    if(lh[1]==rh[1])
      bool=true
    else
      bool=false
    end

    return bool
  end

end

This is what I've got so far, but I can't seem to figure out how to
write methods for: copying a Tda to another Tda, and indexing the Tda.
Thanks for the help!

···

--
Posted via http://www.ruby-forum.com/.

2

Justin To wrote:

class Tda

  def initialize(width=0, height=0)
    if((width==0) && width<height)
      raise NotImplementedError,
      "\(#{width}\) width Tda cannot have a height."
    else
      @tda = Array.new(width).map!{ Array.new(height) }
    end
  end

  def width?
    return @tda.size
  end

  def height?
    if(width?>0)
      return @tda[0].size
    else
      return nil
    end
  end

  #--Returns the dimensional size (x x y) as a string
  def size
    w=@tda.size

    if(width?>0)
      h = @tda[0].size
    else
      h = 0
    end

    return "#{w}x#{h}"
  end

  #--Returns true if both Tda's have equal widths and heights
  def eql_size?(tda)
    bool=false

    lh=size.split('x')
    rh=tda.size.split('x')

    if(lh[0]==rh[0])
      bool=true
    end

    if(lh[1]==rh[1])
      bool=true
    else
      bool=false
    end

    return bool
  end

end

This is what I've got so far, but I can't seem to figure out how to
write methods for: copying a Tda to another Tda, and indexing the Tda.
Thanks for the help!

I haven't tried this, but this method might help -

def copy_tda(original_array)
  new_tda = []
  original_array.each_index do |i|
    new_a = []
    original_array[i].each_index { |j| new_a <<
original_array[i][j].clone }
    new_tda << new_a
  end
  return new_tda
end

···

--
Posted via http://www.ruby-forum.com/.

3

Marshal.dump and Marshal.load might help you.

Todd

···

On Fri, Jun 27, 2008 at 5:23 PM, Justin To <tekmc@hotmail.com> wrote:

This is what I've got so far, but I can't seem to figure out how to
write methods for: copying a Tda to another Tda, and indexing the Tda.

4

class Tda

def initialize(width=0, height=0)
   if((width==0) && width<height)
     raise NotImplementedError,
     "\(#{width}\) width Tda cannot have a height."
   else
     @tda = Array.new(width).map!{ Array.new(height) }
   end
end

def width?
   return @tda.size
end

def height?
   if(width?>0)
     return @tda[0].size
   else
     return nil
   end
end

#--Returns the dimensional size (x x y) as a string
def size
   w=@tda.size

   if(width?>0)
     h = @tda[0].size
   else
     h = 0
   end

   return "#{w}x#{h}"
end

#--Returns true if both Tda's have equal widths and heights
def eql_size?(tda)
   bool=false

   lh=size.split('x')
   rh=tda.size.split('x')

   if(lh[0]==rh[0])
     bool=true
   end

   if(lh[1]==rh[1])
     bool=true
   else
     bool=false
   end

   return bool
end

end

This is what I've got so far, but I can't seem to figure out how to
write methods for: copying a Tda to another Tda, and indexing the Tda.
Thanks for the help!
-- Posted via http://www.ruby-forum.com/.

gem install narray

it's this and *much* *much* more - not to mention insanely fast.

a @ http://codeforpeople.com/

···

On Jun 27, 2008, at 4:23 PM, Justin To wrote:
--
we can deny everything, except that we have the possibility of being better. simply reflect on that.
h.h. the 14th dalai lama

5

Hi --

#--Returns true if both Tda's have equal widths and heights
def eql_size?(tda)
   bool=false

   lh=size.split('x')
   rh=tda.size.split('x')

   if(lh[0]==rh[0])
     bool=true
   end

   if(lh[1]==rh[1])
     bool=true
   else
     bool=false
   end

   return bool
end

See Ara Howard's advice about using narray. Still -- I just wanted to
suggest one or two things to make this method more concise and clear.

One thing you could do is:

   def eql_size?(tda)
     lh=size.split('x')
     rh=tda.size.split('x')

     return lh[0] == rh[0] && lh[1] == rh[1]
   end

In general, it's good to let the comparison methods, like ==, do their
thing, which is to produce true and false. There's usually no need to
store and test the results separately.

Moreover, in this particular case, I think you could just do:

   def eql_size?(tda)
     size == tda.size
   end

:slight_smile:

David

···

On Sat, 28 Jun 2008, Justin To wrote:

--
Rails training from David A. Black and Ruby Power and Light:
   ADVANCING WITH RAILS July 21-24 Edison, NJ
See http://www.rubypal.com for details and updates!

6

Thanks for all the help!

···

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