How To Make Rarity?

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#1

i need help making rarity work

local Ore_Chances = {
	Coal = 0.8;
	Copper = 0.5;
	Gold = 0.25;
	Diamond = 0.15;
}

local function OreRarity()
	for name, chance in Ore_Chances do
		local chosenRarity = (chance / 4) * 100
		if chosenRarity == chance then
			return chosenRarity
		end
	end
end

the math works how i want but wont work since i want to return the name but chosenrarity wont ever be equal to chance because chance isn’t divided/multiplied

This is all i tried and all posts about rarity aren’t very good imo so any help would be awesome

#2

Try returning name instead of chosenRarirty

#3

I could be a bit confused on what your asking but if chosenrarity is never equal with chance, could you not just remove the if statement?

#4

You want to use something called a “Weightage System”. Basically the key is the item and the value is it’s weight. The lower the weight the rarer it is. Then we will select a random number from 1 to the total of all weights combined. After that, we will make a var called counter to which we’ll be adding the weights to compare to the random nu,ber

local Ore_Chances = {
	Coal = 0.8;
	Copper = 0.5;
	Gold = 0.25;
	Diamond = 0.15;
}

local function OreRarity()
    local randnum = Random.new(39473646824):NextNumber(0,1.7) -- 1.7 is total weight
    local counter = 0
	for name, weight in Ore_Chances do
		counter += weight
		if counter > randnum then
			return name
		end
	end
end

This is a very solid RNG system which should be good for general usage

2 Likes
#5

It’d be better if you stated the Random.new() as a variable so all attempts use the same seed so there is no added randomness.

#6

Nice of you to point that out. I’ll make that change now

1 Like
#7 


function getWeightedRandom(weightedList)
	local totalWeight = 0
	for name, v in weightedList do
		totalWeight = totalWeight + v
	end

	local randomWeight = math.random() * totalWeight
	local currentWeight = 0

	for name, v in weightedList do
		currentWeight = currentWeight + v
		if randomWeight <= currentWeight then
			return name
		end
	end
end

local items = {
	Gold = 10,
	Iron = 20,
	Silver = 70,
}
local randomValue = getWeightedRandom(items)
print("Random value:", randomValue)