How to round to 2 Decimal places?

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#1

I got a Value that = 0.984375, and I want it to be rounded to 2 decimals: 0.98
How would I do this?

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How do I fix it?
#2

You could just make a new string of the num, using string.sub, then convert it back to a number

For example,

local number = 0.984375 --original number

local newnumber = string.sub(tostring(number), 1,4)
newnumber = tonumber(newnumber)

To make this a function, do the following:

local function convert(num)
    local newnumber = string.sub(tostring(num), 1,4)
	newnumber = tonumber(newnumber)
	print(newnumber)
end

convert(0.923878327)

There’s probably better ways of doing it, but that’s just 1 way. I would recommend using @SuperSpeedy101’s way, because it’s more efficient and easier.

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#3

Multiply the value by 100
then use math.floor(value)
then divide by 100

example

local value = 0.984375
value *= 100
value = math.floor(value)
value = value / 100
61 Likes
Not Adding 0.1 Correctly
#5

I have an alternative to superspeedy101’s answer:

math.round(number*100)/100

it works, i tested it.

18 Likes
#6

Yes that does work, however math.round is rounding (either doing floor or ceil depending on the decimals) which might have a performance cost and possibly floating point jank, but overall it seems to work the same.

In summary:

Using Luau: math.round(number*100)/100 or math.floor(value*100)/100

Using just Lua: math.floor(value*100)/100 (There is no math.round in vanilla lua)

2 Likes
#7

i see. the only differece is that normal lua doesnt use “math.round” in it’s code.

1 Like
#8

i think i made or pasted a function a while ago to round numbers by decimal places

function math_round(n: number, scale: number?)
    return tonumber(string.format("%." .. (typeof(scale) == "number" and scale or 2) .. "f", n))
end

not sure why math.round doesn’t have a second param by default

7 Likes
#9

sorry to necro, but do you know how i can get this rounded number without a decimal, using the output for an ID but i cant have a decimal, just the numbers

Confusing but, simple

#10

math.round()?

rounds a number without any decimals

#11

i want to take the number and just remove the .

example, i have 5.3892384937, it goes to 5.389, this then goes to 5389

#12

Here’s my function to round numbers to whatever decimal places you want them to.


local function RoundNumber(Number, NumberDecimalPlaces)

	local Rounding = math.floor

	local Digits



	if Number < 0 then
		Number -= (1/(10^(NumberDecimalPlaces+1)))
		Digits = math.ceil(math.log10(math.clamp(Number *-1,0,math.huge)))
		Rounding = math.ceil
	else
		Number += (1/(10^(NumberDecimalPlaces+1)))
		Digits = math.ceil(math.log10(math.clamp(Number,0,math.huge)))
	end


	local Result = Rounding(Number*(10^NumberDecimalPlaces))/(10^NumberDecimalPlaces)

	return Result 

end

print(RoundNumber(-10.52321,2))
1 Like
#13

My initial just thought to do this would be convert it to a string, remove the decimal from the string, and then convert it back to a number.

Also, if you would like to continue this conversation, please open a new thread or go to DMS

#14 
textstring.format("%.f2", yourstring)
--[[                  ^
Allows however many decimals that the number is.
--]]

A simple solution.

3 Likes