Basics

-- Variables (global by default)
x = 10
local y = 20  -- local scope

-- String
local s = "hello " .. "world"  -- concatenation
local len = #s                  -- length

-- Multiple return values
local function minmax(a, b)
  return math.min(a,b), math.max(a,b)
end
local lo, hi = minmax(5, 3)  -- lo=3, hi=5

Tables (Arrays & Maps)

-- Array (1-indexed!)
local arr = {10, 20, 30}
print(arr[1])  -- 10
table.insert(arr, 40)
table.remove(arr, 1)

-- Map / dictionary
local user = {name = "Alice", age = 28}
user.email = "alice@example.com"
print(user["name"])

-- Iterate
for i, v in ipairs(arr) do print(i, v) end
for k, v in pairs(user) do print(k, v) end

OOP with Metatables

local Animal = {}
Animal.__index = Animal

function Animal.new(name, sound)
  return setmetatable({name=name, sound=sound}, Animal)
end

function Animal:speak()
  print(self.name .. " says " .. self.sound)
end

local dog = Animal.new("Dog", "Woof")
dog:speak()  -- Dog says Woof

Standard Library

Module	Key Functions
string	len, sub, find, gsub, format, upper, lower
table	insert, remove, sort, concat, unpack
math	floor, ceil, sqrt, max, min, random, pi
io	read, write, open, close, lines
os	time, date, clock, exit, getenv

Lua Basics Guide

Basics

Tables (Arrays & Maps)

OOP with Metatables

Standard Library

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