Adding to table only if it isn't already in the table

First off, sorry for all the questions.

Now, I have a table, and I want my function only to add a value to the table if it isn't already in the table.

So, say I have a function, and I type in the number 1. The number 1 isn't already in the table, so it adds it. Now I type in the number 1 again. It's already in the table, so it doesn't add it to the table at all. Please help!!!

There's 2 reasonable approaches to this problem, one would be to loop the table everytime you add a value. The other, which i would use, is to use the table keys to store variables, instead of the values themselves.

local t = {}
t[1] = true

now 1 will always be in the table provided i don't change it to nil or false.

Too show what CometWolf meant with loops, Here's an example

local t = {}

local function checkTable( t, value )
	for i, v in ipairs( t ) do
		if v == value then
			return true
		end
	end
	return false
end

table.insert( t, "Hello World" )
local bool = checkTable( t, "Hello World!" )
if bool then
	print( "The value is already in the table" )
else
	print( "The value is not in the table" )
end

I made it a function since I felt it would be easier

Hellkid98, on 30 March 2014 - 05:00 PM said:

Too show what CometWolf meant with loops, Here's an example

local t = {}

local function checkTable( t, value )
	for i, v in ipairs( t ) do
		if v == value then
			return true
		end
	end
	return false
end

table.insert( t, "Hello World" )
local bool = checkTable( t, "Hello World!" )
if bool then
	print( "The value is already in the table" )
else
	print( "The value is not in the table" )
end

I made it a function since I felt it would be easier

That's what I thought. I already had created a loop, but I didn't know how to utilize it.

nateracecar5, on 30 March 2014 - 08:10 PM said:

Hellkid98, on 30 March 2014 - 05:00 PM said:

Too show what CometWolf meant with loops, Here's an example

local t = {}

local function checkTable( t, value )
	for i, v in ipairs( t ) do
		if v == value then
			return true
		end
	end
	return false
end

table.insert( t, "Hello World" )
local bool = checkTable( t, "Hello World!" )
if bool then
	print( "The value is already in the table" )
else
	print( "The value is not in the table" )
end

I made it a function since I felt it would be easier

That's what I thought. I already had created a loop, but I didn't know how to utilize it.

Just copy that code to yours, and then use checkTable("table","value") whenever you want to test the table values.