Lua for loop help!

I have the following code

tile_width = 64;
tile_height = 64;

tile_map = {
    {1,1,1,1,1,1,1,1,1,1,1,1},
    {1,1,1,1,1,3,1,1,1,1,1,1},
    {1,1,1,1,1,3,1,1,1,1,1,1},
    {1,1,1,1,1,3,1,1,1,1,1,1},
    {1,1,1,1,1,3,1,1,1,1,1,1},
    {1,1,1,1,1,1,2,1,1,1,1,1},
    {1,1,1,1,1,1,1,1,1,1,1,1},
    {1,1,1,1,1,1,2,1,1,1,1,1}
}

i=1;
j=1;
while i<table.getn(tile_map) do
    while j<table.getn(tile_map[i]) do
        print(tile_map[i][j]);
        x = (j * tile_width / 2) + (i * tile_width / 2)
        y = (i * tile_height / 2) - (j * tile_height / 2)
        print(x);
        print(y);
        j = j+1;
    end
i = i+1;
end

And it works, but it only di开发者_运维百科splays the first row values, and doesn't go onto the second row, third row, etc.

What I am trying to do in another language

for (i = 0; i < tile_map.size; i++):
    for (j = 0; j < tile_map[i].size j++):
        draw(
            tile_map[i][j],
            x = (j * tile_width / 2) + (i * tile_width / 2)
            y = (i * tile_height / 2) - (j * tile_height / 2)
        )

Any idea what I am doing wrong?

Thanks!

Here is a cleaned up version of your code.

Note changes:

1. Use local variables instead of global.
2. Use # for table size instead of table.getn().
3. Use numeric for loop instead of while.
4. Lack of semicolons.

If you'll uncomment io.write() calls and comment out prints, you will get your map printed out in a readable way.

local tile_width = 64
local tile_height = 64

local tile_map = {
    {1,1,1,1,1,1,1,1,1,1,1,1},
    {1,1,1,1,1,3,1,1,1,1,1,1},
    {1,1,1,1,1,3,1,1,1,1,1,1},
    {1,1,1,1,1,3,1,1,1,1,1,1},
    {1,1,1,1,1,3,1,1,1,1,1,1},
    {1,1,1,1,1,1,2,1,1,1,1,1},
    {1,1,1,1,1,1,1,1,1,1,1,1},
    {1,1,1,1,1,1,2,1,1,1,1,1}
}

for i = 1, #tile_map do
  local row = tile_map[i]
  for j = 1, #row do
    --io.write(row[j])
    print(row[j])
    local x = (j * tile_width / 2) + (i * tile_width / 2)
    local y = (i * tile_height / 2) - (j * tile_height / 2)
    print(x)
    print(y)
  end
  --io.write("\n")
end

P.S. Make sure you've read the Programming in Lua 2nd Edition book. Note that the version, available online, is the first edition and it describes older Lua 5.0.

You have to reset j to 1 after each of the inner loops. Because: After the inner loop has been completed for the first time, j will have been incremented 64 times. But you want to start over with j set to 1.

In the code of the other programming language, note that this re-setting of j is taken care of.