In Lua, how do you find out the key an object is stored in?

Question

How would you print() out or find out the index of an object?

For example, if I spawned 20 random rock objects on screen into an array RockTable = {};<

Answer 1

Unfortunately you'd need to brute the table, to my knowledge. Although, to know that one was clicked, wouldn't you need to be looping them in some way anyway; and therefore already know the index?

Edit

Oh, unless Corona has some sort of callback event for clicking. I've never used it, I've got experience in Lua though.

You could maybe do a backwards reference, like so:

Rocks = {a rock, a rockB, a rockC}
RocksB = {[a rock] = 1, [a rockB] = 2, [a rockC] = 3}

Then just say rockNum = RocksB[rock]

I'm pretty certain that should work but I can't guarantee it, worth a try though.

Edit2

The brute method would look somewhat like:

function getRock(rock)
    for _,v in pairs(rocks) do
        if (v == rock)
            return _
        end
    end
    return "Rock does not exist."
end