Percentage based Chance system

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#1

Basically im trying to make a percentage based chance sytem

however the chance systems i’ve found change depending on the other values, i want these to not change even when the values near them changes, creating a perfect percent

--i hope i didnt mess up the code block :sob:

local Chances = {{"Legendary",3},{"Epic",10},{"Rare",20},{"Uncommon", 50},{"Common",100}}
while true do
	local random = math.random() * 100
	for i,v in pairs(ChanceTable.ChanceTest) do
		if v[2] >= random then
			print(v[1])
		end
	end
task.wait(1)
end

the problem with this code is that if i was to change somethings chance to something else it would break

as an example, if i was to set the uncommons chance to 40 then commons chance would go up from 50% to 60%
how can i make it so that i can change the uncommons chance without having to change commons change

2 Likes
#2

The problem with this percentage based chance system is 50% times it will be common or legendary as its poorly structured

#4

prob made a spelling mistake which made it like that
in game it works perfectly fine
(i rewrote the code while making the post, sorry about the inconsistency)

#5

ok no problem does the new code work better

#6

yes but like i said its not percentage based, when i change the value of uncommon the common’s chance changes with it

#7

ok the problem i mentioned before is that its poorly structured when calculating the percentage

#8

Try using Random.new() instead of math.random()

#9

doesnt Random.new():NextNumber(0,100) do the exact same thing as math.random() * 100

#10

oh yeah my bad i was looking at your code it does the same thing. but the way i would rewrite your code would be different

#11

But then again your right would have to change the rarities to increase chances as if one goes up the other one too.Or you can add a range between chances to prevent common rarity changing.

#12

also the things you’re mentioning have nothing to do with the problem im mentioning

the for i,v in pairs() part of the code checks if v is below or equal to random
assuming that v is 100 (common) it would have a 50% chance of it being picked beacuse if random returns 50 then uncommon would be picked
which means that if random is a number between 100 and 50 it will select common (50%)
if its a number between 50 and 20 it will be uncommon (30%)
if its a number between 20 and 10 it will be rare (10%)
if its a number between 10 and 3 it will be epic (7%)
if the number is below 3 or equal to 3 then it will be legendary

i hope now you understand how the code works

the thing im asking is how can i decrease the uncommons max chance value without accidentally increasing common’s chance

#13

This is more what you’re looking for…

local Chances = {{"Legendary", 1}, {"Epic", 5}, {"Rare", 20}, {"Uncommon", 30}, {"Common", 100}}

while true do
	for _, v in ipairs(Chances) do
		--math.randomseed(tick())
		if math.random(1, 100) <= v[2] then
			print(v[1])
			break
		end
	end	task.wait(1)
end
1 Like
#14

wait but doesnt the math.random constantly change which means there is a small chance of it returning nothing?

#15

No it will always be 1 - 100… A little different way of doing it here along with a drastic difference in the number set up. This approach is to generate a weighted table based on absolute values rather than cumulative probabilities.

#16

wait i was writing the message to debunk your code saying theres a small chance of it returning nothing but im wrong, i think you created the PERFECT percentage based chance system

1 Like
#18

this is good, but i recommend using a weighted chance system for more accuracy

here’s a tutorial i found here on the devforum

1 Like
#19

i found a few problems with weighted chance system hence why i didnt use it

#20

what problems though, im curious

#21

actually now that i think about it doesnt have problems i just saw something i didnt see earlier

still not gonna use it cuz i like writing my own code and also the weighted chance system is much longer

#22

wait is it this? im sorry but idk what “changing values” ur referring to. do u mean changing the value in the table? or is it about creating other variables?