Table in table problem

[likemau5]

Hi guys. I want to make a table with some data, and then make few tables containing the 1st table, and then make operations on them separately(?)

So i have this:

Code: Select all

function love.load()
tab1 = {}
tab1[1] = {a=1,b=1}
tab1[2] = {a=5,b=6}
tab2 = {}
tab2[1] = {tab1 = tab1}
tab2[2] = {tab1 = tab1}
end
function love.update(dt)
tab2[2].tab1[1].a = tab2[2].tab1[1].a + 1 
print("tab1 is " .. tab2[1].tab1[1].a .. "tab2 is " .. tab2[2].tab1[1].a)
end

tab[1].a changes too, i want it to work like tab2[2].tab1[1].a and tab2[1].tab1[1] are separate things? I hope you guys understand me, because english isnt my native languague :/

[s-ol]

Hi guys. I want to make a table with some data, and then make few tables containing the 1st table, and then make operations on them separately(?)

So i have this:

Code: Select all

function love.load()
tab1 = {}
tab1[1] = {a=1,b=1}
tab1[2] = {a=5,b=6}
tab2 = {}
tab2[1] = {tab1 = tab1}
tab2[2] = {tab1 = tab1}
end
function love.update(dt)
tab2[2].tab1[1].a = tab2[2].tab1[1].a + 1 
print("tab1 is " .. tab2[1].tab1[1].a .. "tab2 is " .. tab2[2].tab1[1].a)
end

tab[1].a changes too, i want it to work like tab2[2].tab1[1].a and tab2[1].tab1[1] are separate things? I hope you guys understand me, because english isnt my native languague :/

lua and tables just work like that, if you want to copy a table you need to explicitly create a new table:

instead of

Code: Select all

tab2[1] = {tab1 = tab1}
tab2[2] = {tab1 = tab1}

Code: Select all

tab2[1] = {}
tab2[2] = {}
for k,v in pairs(tab1) do
  tab2[1][k] = v
  tab2[2][k] = v
end

Also note that your whole table setup can be shortened quite a bit like this:

Code: Select all

tab1 = {
  {a=1,b=1},
  {a=5,b=6}
}
tab2 = {  {tab1 = {}},  {tab1 = {}} }

[BOT-Brad]

The issue here is that when you set

Code: Select all

tab2[1] = {tab1 = tab1}

That second tab1 is passed by reference, so will "point" back to the previous object created, not create a new one with the same values.

There are a few ways you could do this, such as use a function which will "copy" the data from the table. Link -> http://lua-users.org/wiki/CopyTable

[likemau5]

Yay thank you guys! Thats exactly what i wanted to achieve