Attempt to perform arithmetic on local 'upgradeCapEfi' (a table value)

Getting Started Newbie Questions
1

I am trying the concept of relational positioning (creating objects based on the location of other objects) and I am having a bit of a problem. I have a text objects inside of circle, and when I try to set its x and y value:

local upgradeCapEfi = display.newCircle(left + 20, bottom, 50) upgradeCapEfi.fill = \_PURPLE\_ local upgradeText = display.newText("Upgrade: \nLevel " .. moneyLVL, 0, 0, 100, 0, native.systemFont, 10) upgradeText.x, upgradeText.y = upgradeCapEfi.x + 20, upgradeCapEfi - 20

I get an error saying  “Attempt to perform arithmetic on local ‘upgradeCapEfi’ (a table value)” Why is the circle’s coordinates a table value?

2

upgradeCapEfi.y

not

upgradeCapEfi

upgradeText.x, upgradeText.y = upgradeCapEfi.x + 20, upgradeCapEfi.y - 20
3

If you’re new, you should avoid doing this:

upgradeText.x, upgradeText.y = upgradeCapEfi.x + 20, upgradeCapEfi.y - 20

 and do this instead:

upgradeText.x = upgradeCapEfi.x + 20 upgradeText.y = upgradeCapEfi.y - 20

It will make debugging much easier since the bug has the line number in it and with only one statement to debug it will be clear.

4

Oops, careless mistake.

Thanks for pointing this out!

5

I want to echo @roaminggamer’s advice. Even if you’re an experienced developer, there is value to writing clear code. While Lua allows you to assign multiple variables in one assignment statement and it saves a few lines of code, it makes the code harder to follow and you can easily miss a misspelled variable name that with Ed’s suggestion would stand out and be easily spotted.

Rob

6

Thanks, I will keep this in mind.

7

upgradeCapEfi.y

not

upgradeCapEfi

upgradeText.x, upgradeText.y = upgradeCapEfi.x + 20, upgradeCapEfi.y - 20
8

If you’re new, you should avoid doing this:

upgradeText.x, upgradeText.y = upgradeCapEfi.x + 20, upgradeCapEfi.y - 20

 and do this instead:

upgradeText.x = upgradeCapEfi.x + 20 upgradeText.y = upgradeCapEfi.y - 20

It will make debugging much easier since the bug has the line number in it and with only one statement to debug it will be clear.

9

Oops, careless mistake.

Thanks for pointing this out!

10

I want to echo @roaminggamer’s advice. Even if you’re an experienced developer, there is value to writing clear code. While Lua allows you to assign multiple variables in one assignment statement and it saves a few lines of code, it makes the code harder to follow and you can easily miss a misspelled variable name that with Ed’s suggestion would stand out and be easily spotted.

Rob

11

Thanks, I will keep this in mind.