numbers.md

Understanding Number Data Types

Introduction

What are Numbers or Doubles ?

In Luau, numbers, also knows as doubles, represent double-precision (64-bit) floating-point values. They cover a vast range, from -1.7 * 10^308 to 1.7 * 10^308, providing around 15 digits of precision, whether positive or negative.

Signed and Unsigned

The sign of a number indicates its positivity or negativity. For instance, 1 is positive, and -1 is negative. Remarkably, in Luau, -0 is equivalent to 0.

print(0 == -0) --> true
print(-0 > 1) --> false
print(-0 < 1) --> true
print(-0 > -1) --> true
print(-0 < -1) --> false

Number Classifications

While Luau doesn't explicitly differentiate between integers and numbers, some API references make this distinction for specific use cases.

• Float

  • The float type represents numbers with decimals, like 1.5 or -0.75. It's good for mast uses, not as precise as some, but id saves memory.

• Integers

  • The intergers are whole numbers, like 5 or -100. They're good for counting and measuring things if a function needs an integerm it might round or giver an error if you try to use a non-whole number.

• Int64

  • The Int64 is a big whole number type. It's often used for IDs in Roblox, like Player.UserId. Some Roblox functions, sunch as MarketplaceService:PromptPurchase() and TeleportService:Teleport() want these big numbers as inputs.

Number Notation

In Roblox Lua, numbers are written in different ways:

• Decimal (base-10)

  • Write the digits normally with an optional decimal point.
  • For example: 7, 1.25, or -22.5.

• Scientific Notation

  • Write a dicimal number followed by e or e+ and an integer.
  • For example: 12e3 is 12 x 10^3 (12.000).

• Hexadecimal (base-16)

  • Start the number with 0x, followed by 0-9 or A-F (case insensitive).
  • For example: 0xF is 15, and 0x3FC is 1020.

• Binary (base-2)

  • Start the number with Ob followed by 0s or 1s.
  • For example: Ob1100 represents 12 in decimal format.

For long numbers, you can optionally use underscores to improve readability, except at the beginning. For example, 1_234_567 is the same as 1234567, both of which are equivalent to 1,234,567.

Operations

In Luau, you can do things with numbers using operators. There are two types:

• Logical And Relational Operators

  • They help you compare and manipulate numbers.

  • Examples include comparingg if one number is greater than another or checking if two numbers are equal.

    local a = 5
    local b = 10
    
    print(a > b) --> false
    print(a == b) --> false

• Mathematical Functions

  • You can also use special math functions for more complex operations

  • Examples are math.sqrt() (square root) and math.exp() (exponential)

    local x = 25
    
    print(math.sqrt(x)) --> 5
    print(math.exp(x)) --> around 720.05

  • These functions are part of the math library in Luau.

• Bitwise Operations

  • For even more advanced operations, you can use bitwise operations from the bit32 library.

  • These operations work on the individual bits of numbers.

    local m = 5
    local n = 3
    
    print(bit32.band(m, n)) --> 1 (bitwise AND)
    print(bit32.bord(m, n)) --> 7 (bitwise OR)

These tools give you the power to play with numbers in different ways!

Type Introspection

Determining if a value is a number

In Luau, figuring out if something is a number is easy. You can use either type(x) or typeof(x), and both will tell you if x is a number. They will say say number if it is.

  local testInt = 5
  local testDecimal = 9.12761656
  local testString = "Hello"

  -- Using type()
  print(type(testInt)) --> number
  print(type(testDecimal)) --> number
  print(type(testString)) --> string

  -- Using typeof()
  print(typeof(testInt)) --> number
  print(typeof(testDecimal)) --> number
  print(typeof(testString)) --> string

So, if you ever wonder whether a value like testInt, testDecimal, or testString is a number, just use one of these methods, and they'll give you a clear answer.

Rounding Functions

How to Do Number Rounding Easily?

You can easily round numbers using three functions: math.floor(), math.ceil(), and math.modf().

• Determinate if a Number is an Integer

  • To check if a number x is an integer, you can use the expression math.floor(x) == x

• Round a Number Down

  • To round a number down, simply use math.floor().

  • It returns the largest integer less than or equal to the given number.

    print(math.floor(3.3)) --> 3
    print(math.floor(-3.3)) --> 4

• Round a Number Up

  • For rouding a number up to the nearest integer, use math.ceil().

  • This function returns the smallest integer greater than or equal to the provided number.

    print(math.ceil(3.3)) --> 4
    print(math.ceil(-3.3)) --> -3

• Round a Number Towards Zero

  • When you want to round a number towards zero and also get the fractional difference, use math.modf().
  • It returns two values: the integer part and the fractional part.

    print(math.modf(3.3)) --> 3 0.3
    print(math.modf(-3.3)) --> -3 -0.3

These simple functions make rouding number a breeze in Luau!