Dave H. wrote:
OK, let’s try this from the top. {grin} Here’s some fresh new code:
Thx again - very instructive.
I have managed to get the capping working in isolation as per the
following code:
class Array2D
Delta=[[0,0], [0,-1], [1,-1], [1,0], [1,1], [0,1], [-1,1], [-1,0],
[-1,-1]]
attr_reader :width, :height
attr_accessor :cell_content
def initialize(width, height, cell_content)
@width = width
@height = height
@data = Array.new(@height) {Array.new(@width){|i| cell_content} }
end
def [](x, y, z)
deltaX, deltaY = *Delta[z]
x = (x + deltaX) % @width
y = (y + deltaY)
@data[y][x] unless y<0 or y>(@height-1)
end
def []=(x, y, z, value)
deltaX, deltaY = *Delta[z]
x = (x + deltaX) % @width # modulus % allows wrapping
y = (y + deltaY)
@data[y][x] = value unless y<0 or y>(@height-1)
end
def display
@height.times {|rownum| print(@data[rownum].join(" ") + “\n”)};nil
end
end
a=Array2D.new(10,5,“X”)
m = rand(10)
n = rand(5)
a[m,n,0] = “A”
a[m,n,1] = “H”
a[m,n,2] = “H”
a[m,n,3] = “H”
a[m,n,4] = “A”
a[m,n,5] = “A”
a[m,n,6] = “A”
a[m,n,7] = “A”
a[m,n,8] = “A”
puts a.display
However, it still falls over when I try to insert the above into my main
program, as below:
class Array2D
Delta=[[0,0], [0,-1], [1,-1], [1,0], [1,1], [0,1], [-1,1], [-1,0],
[-1,-1]]
attr_reader :width, :height
def initialize(width, height)
@width = width
@height = height
@data = Array.new(@height) {Array.new(@width) {|i|“X”}}
end
def [](x, y, z)
deltaX, deltaY = *Delta[z]
x = (x + deltaX) % @width
y = (y + deltaY)
@data[y][x] unless y<0 or y>(@height-1)
end
def []=(x, y, z, value)
deltaX, deltaY = *Delta[z]
x = (x + deltaX) % @width # modulus % allows wrapping
y = (y + deltaY)
@data[y][x] = value unless y<0 or y>(@height-1)
end
def display
@height.times {|rownum| print(@data[rownum].join(" ") + “\n”)};nil
end
end
class World < Array2D
attr_reader :size
def initialize(size)
@rows = size
@cols = @rows * 2
@world = Array2D.new(@cols, @rows)
end
def populate_array_cells_with_hash
(0…@rows).each do |b|
(0…@cols).each do |a|
@world[a,b,0] = {
“hex_col_no” => a,
“hex_row_no” => b,
“hex_id_A” => "X ",
“hex_id_B” => nil,
“hex_id_C” => nil,
“hex_id_D” => nil,
“hex_id_E” => nil,
}
end
end
end
def insert_teleporting_square
m = rand(@cols)
n = rand(@rows)
@world[m,n,0][“hex_id_A”] = "A "
@world[m,n,1][“hex_id_A”] = "H "
@world[m,n,2][“hex_id_A”] = "H "
@world[m,n,3][“hex_id_A”] = "H "
@world[m,n,4][“hex_id_A”] = "A "
@world[m,n,5][“hex_id_A”] = "A "
@world[m,n,6][“hex_id_A”] = "A "
@world[m,n,7][“hex_id_A”] = "A "
@world[m,n,8][“hex_id_A”] = "A "
end
def print_world(type)
(0…@rows).each do |b|
puts
(0…@cols).each do |a|
print @world[a,b,0][type]
end
end
end
end
first_world = World.new(5)
first_world.populate_array_cells_with_hash
first_world.insert_teleporting_square
first_world.print_world(“hex_id_A”)
puts
It falls over when it hits one of these two lines:
@world[m,n,1][“hex_id_A”] = "H "
@world[m,n,4][“hex_id_A”] = "A "
With error as before:
undefined method `[]=’ for nil:NilClass (NoMethodError)
What my program does is generate an array, then populates each cell of
that array with a hash. It looks like when it tries to access the hash
values outside the array boundary it runs into problems? Do I need
another method inside the Array2D class to deal with hash access? If so,
how can this be done? If not, can anyone see any other reason for the
error?
