[QUESTION][HELP] Table...

I'm trying to figured out why tables are helpful and why should i learn them. I tryed to use them, but i'm pretty sure i'm not doing it the right way.

Here's what i know : to do a table you do

t = {the stuff, other stuff, random stuff}
[code/]

so for the sake of not being random: should i need a table for that situation? How do i use it????????



[code]
--it's a googling engine(lkinda)
function finder()
screen()
local food = {"cake", "bread", "pork", "steak", "sugar", "chicken"}
local tool = {"armor", "pickaxe", "shovel", "axe", "sword", "other"}

if input1 == food.cake then
  print("work")
end
end

thanks for answering this noobish question

EDIT: I've look through every tutorial i found, still confused

http://www.lua.org/pil/2.5.html
If you're still confused after why one would want to use tables, then it might be a little bit more helpful if you could specify exactly why you're pondering the question to begin with? That way it might be a bit easier to tell you why you'd want to use tables in a specific situation, rather than not.
It always depends on the need of a situation.

Try this

t = {the stuff, other stuff, random stuff}
food = {"cake", "bread", "pork", "steak", "sugar", "chicken"}
tool = {"armor", "pickaxe", "shovel", "axe", "sword", "other"}

--it's a googling engine(lkinda)
function finder()
    screen()
    for i = 1, #food do
        if input1 == food[i] then
          print("Worked! You entered: "..input1.." which is in the food table!")
          break
        end
    end
end

sIdEkIcK_, on 18 November 2012 - 04:56 AM said:

Try this

t = {the stuff, other stuff, random stuff}
food = {"cake", "bread", "pork", "steak", "sugar", "chicken"}
tool = {"armor", "pickaxe", "shovel", "axe", "sword", "other"}

--it's a googling engine(lkinda)
function finder()
	screen()
	for i = 1, #food do
		if input1 == food[i] then
		  print("Worked! You entered: "..input1.." which is in the food table!")
		  break
		end
	end
end

Ok thanks, it's a bit more precise on how to use it.

Espen, on 18 November 2012 - 03:52 AM said:

http://www.lua.org/pil/2.5.html
If you're still confused after why one would want to use tables, then it might be a little bit more helpful if you could specify exactly why you're pondering the question to begin with? That way it might be a bit easier to tell you why you'd want to use tables in a specific situation, rather than not.
It always depends on the need of a situation.

it's helping but my situation need for each "variable(if i can call them so)" to have a description on each. Here would be the material it need to build that specific item. So if

input = read() -- here i write cake

I'd like to read the material list of the cake (that i would enter in a variable i guess????)

thanks, if i'm not precise enought tell me

In that case, you could do this:

local recipes = {}
recipes.cake = "eggs + milk + sugar"
recipes.tnt = "sand + gun powder"

local input = read()
local recipe =  recipes[input]
if recipe then
  print("Recipe for '"..input.."' is: "recipe)
else
  print("Recipe for '"..input.."' not found!")
end

Of course, you wouldn't put just a descriptive string for the recipes.. You could make it another table with ingredients, or just 3 strings or something for the crafting. Be creative. :)/>/>

Would it be possible to add multiple function to a table, as for exemple :

input = read()

t = [ cake, apple, bread]

function bread()
   term.setCursorPos(10, 1)
   print("You'll need 3 wheat")
   print("Add all the ingredient on the same row")
end

recipe = t[ input ]
if recipe then
   t[input]--i guess it's the code that would be there
end

I've put only one function for the sake of the exemple.

You did make some mistakes in your code (like using [ ] for some reason). Anyway, you could do it like this:

local recipes = {}
recipes.cake = function()
  -- cake function
end
recipes.tnt = function()
  -- tnt function
end
local input = read()
local recipeFunc =  recipes[input]
if recipeFunc then
  recipeFunc()
else
  print("Recipe for '"..input.."' not found!")
end

Orwell, on 18 November 2012 - 06:46 AM said:

You did make some mistakes in your code (like using [ ] for some reason). Anyway, you could do it like this:

local recipes = {}
recipes.cake = function()
  -- cake function
end
recipes.tnt = function()
  -- tnt function
end
local input = read()
local recipeFunc =  recipes[input]
if recipeFunc then
  recipeFunc()
else
  print("Recipe for '"..input.."' not found!")
end

For the bracket, my bad :)/>/> .
Thanks it's much more clearer now, i'll try to use them in my code.

Ok next question, is it possible to search through multiple table at the same time something like :

local recipe = {food, tool, smelting}

local food = {}
food.cake = cake()
local tool = {}
tool.shovel = shovel()
local smelting = {}
smelting.ore = ore()

function function() --just to get the general idea
 
input = read()

find = recipe[input]

if find then
   find()
end

Did i get it right ??

crackroach, on 18 November 2012 - 09:43 AM said:

Ok next question, is it possible to search through multiple table at the same time something like :

local recipe = {food, tool, smelting}

local food = {}
food.cake = cake()
local tool = {}
tool.shovel = shovel()
local smelting = {}
smelting.ore = ore()

function function() --just to get the general idea

input = read()

find = recipe[input]

if find then
   find()
end

Did i get it right ??

No. :D/>/> It would be more like:

local food = {}
food.cake = function () end
local tool = {}
tool.shovel = function () end
local smelting = {}
smelting.ore = function () end
local recipe = {food, tool, smelting}
function main() --can't be called function :)/>/>

input = read()
for i,v in pairs(recipe) do
  find = recipe[v][input]

  if find then
	 find()
	 break
  end
end

Better way to do this, is just using my previous example, but adding a 'type' value to each recipe (tool, food, smelting,…). So you still have one big table and you still can check what category it is in.

Orwell, on 18 November 2012 - 10:20 AM said:

crackroach, on 18 November 2012 - 09:43 AM said:

Ok next question, is it possible to search through multiple table at the same time something like :

local recipe = {food, tool, smelting}

local food = {}
food.cake = cake()
local tool = {}
tool.shovel = shovel()
local smelting = {}
smelting.ore = ore()

function function() --just to get the general idea

input = read()

find = recipe[input]

if find then
   find()
end

Did i get it right ??

No. :D/>/> It would be more like:

local food = {}
food.cake = function () end
local tool = {}
tool.shovel = function () end
local smelting = {}
smelting.ore = function () end
local recipe = {food, tool, smelting}
function main() --can't be called function :)/>/>

input = read()
for i,v in pairs(recipe) do
  find = recipe[v][input]

  if find then
	 find()
	 break
  end
end

Better way to do this, is just using my previous example, but adding a 'type' value to each recipe (tool, food, smelting,…). So you still have one big table and you still can check what category it is in.

Wow that's perfect, you're really helping me out with this, very appreciated.

I guess it will be easier to aak question with the proper problem. I've copied parts of your code in an attempt to understand each part while trying to run it and modify it, but i only crashed into error at line 57

so here's my code for dico program:

sizeX, sizeY = term.getSize()
function screen()
 term.clear()
 term.setCursorPos(14, 1)
 print("Minecraft recipe guide")
end

-- TABLES
 
 
 local food = {}
 food.cake = function()
  term.clear()
  print("worked")
  screen()
 end
  
  
 local tool = {}
 tool.shovel = function() end
 local smelting = {}
 smelting.ore = function() end
 local recipe = {food, tool, smelting}
 
function askBox()
 local a = "----------------"
 term.setCursorPos(sizeX - 16, 3)
 print(a)
end
 
function ask()
 screen()
 term.setCursorPos(sizeX -25 , 2)
 print("Search : ")
 askBox()
 term.setCursorPos(sizeX - 16, 2)
 input1 = read()
 sleep(0.5)
 term.clear()
 term.setCursorPos(((sizeX / 2) - 10), (sizeY / 2))
 textutils.slowPrint("Looking for "..input1, 18)
 sleep(1)
 return input1
end
 
 
function finder()
 screen()
 for i,v in pairs(recipe) do 
  find = recipe[v][input]  --line 57
  if find then		
   find()		
   break 
  end
 end
end
function main()
 screen()
 ask()
 finder()
end
main()

when i try to run it CC tell's me : dico:57: attempt to index ? (a nil value)

My bet you'd be that the problem come's from that variable "v" since it's undefined. I don't know how to define it, i've tryed but still got that error.

Any advice?

"v" is definitely defined, "recipe[v]" probably isn't. You should check if recipe[v] exists, before trying to find recipe[v][input].

Scratch that, evidently, "v" is "recipe[v]", so you would just do v[input].

Yes, I messed up there. :)/>/> v represents one of the three tables in the table recipe.