Variables & Data Types in Lua

Lua is a dynamically typed language, which means variables don't have types, only values do. In this tutorial, we'll explore Lua's variable system and its basic data types.

Variable Declaration

In Lua, variables are global by default. To create a local variable, use the local keyword:

-- Global variable
globalVar = 10

-- Local variable
local localVar = 20

Basic Data Types

Lua has eight basic types:

nil - represents the absence of a value
boolean - true or false
number - represents both integers and floats
string - sequence of characters
function - reusable code blocks
userdata - allows C data to be stored in Lua variables
thread - independent threads of execution
table - the only data structure in Lua (arrays, dictionaries, objects)

Type Function

You can check a value's type using the type() function:

print(type("Hello"))    -- string
print(type(10.4))      -- number
print(type(print))     -- function
print(type(true))      -- boolean
print(type(nil))       -- nil

Strings

Strings can be enclosed in single or double quotes:

local str1 = "Hello"
local str2 = 'World'
local multiLine = [[
This is a multi-line
string in Lua
]]

Tables

Tables are Lua's only data structure but are incredibly flexible:

-- Array-like table
local arr = {10, 20, 30}

-- Dictionary-like table
local dict = {name = "Lua", version = "5.4"}

Next Steps

Now that you understand variables and data types, learn about control structures in Lua.