Multi-dimensional arrays not working

ruby-talk
1

I am trying to make a 3D grid using an Array of Arrays of Arrays but am
having trouble storing a single point with a value:

#2 by 2 by 2 grid
@grid = Array.new(2, Array.new(2, Array.new(2, "Null")))

#Point (x, y, z)
#Point (0, 1, 1)
@grid[0][1][1] = 'd'

#Print several points in grid
puts @grid[0][0][1]
puts @grid[0][1][1]
puts @grid[1][1][1]
puts @grid[0][0][0]
puts @grid[0][1][0]
puts @grid[1][1][0]

The code returns all values with z = 1 as 'd' and z = 0 as 'null'... It
should really be only making the point (0, 1, 1) as 'd' right?!?!?

If the above line "@grid[0][1][1] = 'd'" is changed, the only value that
will change the results is the z value...

I want it so that only "puts @grid[0][1][1]" returns 'd'... The actual
code contains more methods and stuff, but I think I've isolated the
problem to this... Any info, tutorials, links, or code would be greatly
appreciated.

···

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2

Array's initial value is not copied to each block, but every field
indicates the same object.
So, @grid should be initialized in the following way.

   @grid = Array.new(2).collect{ Array.new(2).collect{
Array.new(2).collect{ "Null"}}}

On ruby 1.7 or later,
   @grid = Array.new(2){ Array.new(2){ Array.new(2){ "Null"}}}
is OK, too.

There are some sample codes for such case.
Sorry, I could not find English edition.
http://www.ruby-lang.org/ja/man/html/trap_Array.html

···

On Sun, Mar 6, 2011 at 8:36 AM, Jesse Jurman <e.j.jurman@gmail.com> wrote:

I am trying to make a 3D grid using an Array of Arrays of Arrays but am
having trouble storing a single point with a value:

#2 by 2 by 2 grid
@grid = Array.new(2, Array.new(2, Array.new(2, "Null")))

#Point (x, y, z)
#Point (0, 1, 1)
@grid[0][1][1] = 'd'

#Print several points in grid
puts @grid[0][0][1]
puts @grid[0][1][1]
puts @grid[1][1][1]
puts @grid[0][0][0]
puts @grid[0][1][0]
puts @grid[1][1][0]

The code returns all values with z = 1 as 'd' and z = 0 as 'null'... It
should really be only making the point (0, 1, 1) as 'd' right?!?!?

If the above line "@grid[0][1][1] = 'd'" is changed, the only value that
will change the results is the z value...

I want it so that only "puts @grid[0][1][1]" returns 'd'... The actual
code contains more methods and stuff, but I think I've isolated the
problem to this... Any info, tutorials, links, or code would be greatly
appreciated.

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

--
Haruka YAGNI
hyagni@gmail.com

3

Haruka YAGNI wrote in post #985681:

Array's initial value is not copied to each block, but every field
indicates the same object.
So, @grid should be initialized in the following way.

   @grid = Array.new(2).collect{ Array.new(2).collect{
Array.new(2).collect{ "Null"}}}

Thanks! Worked perfectly... I was trying to figure out why it wasn't
working... makes a lot more sense now though.

···

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