Getting a unique set of values from a table for multiple strings

Solar2D Lua Language
#1

Hi All

Im trying to come up with the most efficient way to do this but can’t seem to get to an end point, tried a while statement but that only compares one value to another.

I have these coordinates on a screen set in a table array:

cordx = {
        [1] = 160,
        [2] = 260,
        [3] = 60

    } 

cordy = {
        [1] = 100,
        [2] = 250,
        [3] = 400
    }

x = cordx[math.random(1,3)]
y = cordy[math.random(1,3)]

But I want to assign x and y to 9 objects on the screen. However, I would like all of them to be placed in a unique set.

e.g.

object 1 = 160 (x), 100 (y)

object 2 = 160 (x), 250 (y)

object 3 = 60 (x), 100 (y)

But no clashes or overlaps of more than 1 object on the same coordinate x & y.

Any help would be greatly appreciated

#2

I think this will help.

Basically make a table with all possible coordinates.

[lua]local cordx = {160, 260, 60} 

local cordy = {100, 250, 400}

local allCords = {}

for x = 1, #cordx do

    for y = 1, #cordy do

        allCords[#allCords+1] = {cordx[x], cordy[y]}

    end

end[/lua]

Probably you want it to be random? If so google how to shuffle a Lua table. Then loop through the table and take your coordinates:

[lua]for i = 1, #allCords do

    print(“x”, allCords[i][1], “y”, allCords[i][2])

end[/lua]

#3

This is brilliant, thanks a lot. I can shuffle the table but how do I call the pair of values in my object?

num1 = display.newText( 1, 60, 100, native.systemFont, 50 )
num2 = display.newText( 2, 160, 100, native.systemFont, 50 )
num3 = display.newText( 3, 260, 100, native.systemFont, 50 )

Im trying to get each of these to take a pair from the table it says Im getting a Nil value?

#4

So in allCords you have both X and Y. 

allCords[1] holds first position and allCords[1][1] holds X and allCords[1][2] holds Y for first position.

In your example:

num1 = display.newText( 1, allCords[1][1], allCords[1][2], native.systemFont, 50 )

num2 = display.newText( 2, allCords[2][1], allCords[2][2], native.systemFont, 50 )
num3 = display.newText( 3, allCords[3][1], allCords[3][2], native.systemFont, 50 )

The above method is a lot of repetitive code which eventually becomes a mess. Think about something like this instead.

local numbers = {}

for i = 1, #allCords do

    numbers[i] = display.newText( i, allCords[i][1], allCords[i][2], native.systemFont, 50 )

end

#5

That worked, you’ve been most helpful, yes I know my code is quite messy at the moment, the cleanup will come once done hopefully. Needless to say, I am also quite new to all this so my logical brain is lacking !

#6

Glad to help. I think most important thing to learn sooner rather than later is about tables. Lua will be putty in your hands after that!

#7

I think this will help.

Basically make a table with all possible coordinates.

[lua]local cordx = {160, 260, 60} 

local cordy = {100, 250, 400}

local allCords = {}

for x = 1, #cordx do

    for y = 1, #cordy do

        allCords[#allCords+1] = {cordx[x], cordy[y]}

    end

end[/lua]

Probably you want it to be random? If so google how to shuffle a Lua table. Then loop through the table and take your coordinates:

[lua]for i = 1, #allCords do

    print(“x”, allCords[i][1], “y”, allCords[i][2])

end[/lua]

#8

This is brilliant, thanks a lot. I can shuffle the table but how do I call the pair of values in my object?

num1 = display.newText( 1, 60, 100, native.systemFont, 50 )
num2 = display.newText( 2, 160, 100, native.systemFont, 50 )
num3 = display.newText( 3, 260, 100, native.systemFont, 50 )

Im trying to get each of these to take a pair from the table it says Im getting a Nil value?

#9

So in allCords you have both X and Y. 

allCords[1] holds first position and allCords[1][1] holds X and allCords[1][2] holds Y for first position.

In your example:

num1 = display.newText( 1, allCords[1][1], allCords[1][2], native.systemFont, 50 )

num2 = display.newText( 2, allCords[2][1], allCords[2][2], native.systemFont, 50 )
num3 = display.newText( 3, allCords[3][1], allCords[3][2], native.systemFont, 50 )

The above method is a lot of repetitive code which eventually becomes a mess. Think about something like this instead.

local numbers = {}

for i = 1, #allCords do

    numbers[i] = display.newText( i, allCords[i][1], allCords[i][2], native.systemFont, 50 )

end

#10

That worked, you’ve been most helpful, yes I know my code is quite messy at the moment, the cleanup will come once done hopefully. Needless to say, I am also quite new to all this so my logical brain is lacking !

#11

Glad to help. I think most important thing to learn sooner rather than later is about tables. Lua will be putty in your hands after that!