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problem with for statement and tables

 
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Mr Billy



Joined: 26 Oct 2005
Posts: 10
PostPosted: Fri Dec 23, 2005 10:40 am    Post subject: problem with for statement and tables Reply with quote
i have two tables, one holding my images(tiles) and one holding the layout of the tiles. i am using a for statement so i dont have many lines of code. when i use this code, i get an "attempt to index field '?' (a nil value)" error on the blit line. if i replace the y in layout[y] for a number, it seems to work. why doesnt it work with a variable?

Code:
for y=1,16 do
     screen:blit(0, ((y*32)-32), images[layout[y].block1])
end


thanks
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romero126



Joined: 24 Dec 2005
Posts: 200
PostPosted: Sat Dec 24, 2005 4:25 pm    Post subject: Reply with quote
Your Code
Code:

for y=1,16 do
     screen:blit(0, ((key*32)-32), images[layout[y].block1])
end


Try this its simpler and will never give you any issues.
This is to make shure the table Images has what your looking for.
Code:

for key,value in layout do
     if (images[value.block1]) then
          screen:blit(0, ((key*32)-32), images[value.block1])
     end
end

The code Checks if the value exists before trying to print it.
So you dont have errors like that if the data is nothing. Also it goes through the entire loop so you can set it with another statement.
If you just want it to do up to number 16 (that is if you numbered it)
Code:

     if (images[value.block1]) and (key <= 16) then
          screen:blit(0, ((key*32)-32), images[value.block1])
     end


*Edited for typo' in key (Within code)
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