CODEWITHSUNDEEP
lualua-table
user2021539
user2021539

Reputation: 967

Trying to build a table of unique values in LUA

I am trying to build a table and add to it at the end each time I get a returned value that is not already in the table. So basically what I have so far is not working at all. I'm new to LUA but not to programming in general.

local DB = {}
local DBsize = 0

function test()
  local classIndex = select(3, UnitClass("player")) -- This isn't the real function, just a sample
  local cifound = False

  if classIndex then
    if DBsize > 0 then
      for y = 1, DBsize do
        if DB[y] == classIndex then 
          cifound = True
        end
      end
    end

    if not cifound then 
      DBsize = DBsize + 1
      DB[DBsize] = classIndex
    end
  end
end

Then later I'm trying to use another function to print the contents of the table:

        local x = 0

        print(DBsize)
        for x = 1, DBsize do
            print(DB[x])
        end

Any help would be much appreciated

Upvotes: 2

Views: 3087

Answers (2)

James Isaac Neutron
James Isaac Neutron

Reputation: 1

This could work, but one thing you could do (which is an extra step, but works) is that if you're trying to store only unique values, you can create a "table contains" function.

Here's teh gist of what I did:

tablecontains(table2process, valuetosearch)
   if next(table2process) == nil then
      return false
   else
      for i = 1, #table2process do
         if table2process[i] == value then
            return true
         end
      end
      return false
   end
end

Explanation:

  1. Code Checks to see if table you're passing is empty. If so, return false

  2. Code then checks every value in the table to ensure the value you're searching for isn't in each element in the table.
    2a. If it DOES exist, the function returns true

  3. The for loop exits, and an unconditional return false is provided (this ensures that if NO value is found in the table, it's safe to be inserted as a unique value).

Usage: Here's how I use it in my code:

if not tablecontains(tabletouse, searchquery) then
   table.insert(tabletouse, searchquery)
end

This allows you to only insert what exists within your table beit strings, or other types of values (im using strings!)

Upvotes: 0

Piglet
Piglet

Reputation: 28950

Just store a value in the table using your unique value as a key. That way you don't have to check wether a value already exists. You simply overwrite any existing keys if you have it a second time.

Simple example that stores unique values from 100 random values.

local unique_values = {}

for i = 1, 100 do
  local random_value = math.random(10)
  unique_values[random_value] = true
end

for k,v in pairs(unique_values) do print(k) end

Upvotes: 6

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