dual for loop instance error

[RoadhammerGaming]

Hi, I am trying to compare the x and y positions of 2 instances to check for a collision, in my project I may have any number of instances of object enemy and object weapon, so I thought I could check for this by using a nested for loop, this is my code:

Code: Select all

   for j = #enemy, 1, -1 do
       local oE = enemy[j]
       if (o.x + 20) > oE.xX and (o.x +20) < oE.xX + 41 and (o.y + 22) > oE.yYX and (o.y +22) < oE.yYX + 45 then 
       points = points + (10 * level)
			table.remove(weapon, i)
			table.remove(enemy, j)
		end	
   end

and this is the error code I'm getting:


I am new at love2d and lua, so imagine I'm overlooking something or doing something wrong, can anyone tell me what could be the problem or steer me in the right direction? thanks

[grump]

Hi, I am trying to compare the x and y positions of 2 instances to check for a collision, in my project I may have any number of instances of object enemy and object weapon, so I thought I could check for this by using a nested for loop, this is my code:

There is no nested loop in the code you posted, and if I'm not mistaken, this code can't produce the error message.

You're trying to compare a variable that's not been initialized (nothing has been assigned to it) with a number. Since you're adding numbers to all the variables on the left side of your comparison operators (< and >), your code would throw "attempt to perform arithmetic on a nil value", not "attempt to compare nil with a number" if those vars were nil. There is no way this code results in your error.

Please check again and post the relevant code.

[RoadhammerGaming]

Hi, I am trying to compare the x and y positions of 2 instances to check for a collision, in my project I may have any number of instances of object enemy and object weapon, so I thought I could check for this by using a nested for loop, this is my code:

There is no nested loop in the code you posted, and if I'm not mistaken, this code can't produce the error message.

You're trying to compare a variable that's not been initialized (nothing has been assigned to it) with a number. Since you're adding numbers to all the variables on the left side of your comparison operators (< and >), your code would throw "attempt to perform arithmetic on a nil value", not "attempt to compare nil with a number" if those vars were nil. There is no way this code results in your error.

Please check again and post the relevant code.

Oh sorry about that I didn't paste the whole loop, this should be all of it:

for i = #weapon, 1, -1 do
local o = weapon

for j = #enemy, 1, -1 do
local oE = enemy[j]
if (o.x + 20) > oE.xX and (o.x +20) < oE.xX + 41 and (o.y + 22) > oE.yYX and (o.y +22) < oE.yYX + 45 then
points = points + (10 * level)
table.remove(weapon, i)
table.remove(enemy, j)
end
end

if (o.x < -10) or (o.x > love.graphics.getWidth() + 10)
or (o.y < -10) or (o.y > love.graphics.getHeight() + 10) then
table.remove(weapon, i)
end
end

AAAHHHH and I see exactly what I did wrong!! I misspelled The variables xX and yY in the last part of the comparison, that's embarrassing sorry for this post and thanks for your help.