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Comments

Part of the Fundamentals section of Coddy's Lua journey — lesson 3 of 90.

Comments are notes you write inside your code. Lua completely ignores them - they exist only to help humans understand the code.

To write a single-line comment, use two dashes --. Everything after -- until the end of the line is ignored:

-- This is a comment
print("Hello World!")

A comment can also be written at the end of a line, after the code:

print("Hello World!") -- This prints Hello World!

For comments that span several lines, use --[[ to start and ]] to end:

--[[
This is a multi-line comment.
Lua ignores all of it.
]]
print("Welcome!")

Comments can also temporarily disable a line of code without deleting it:

-- print("This line will NOT run")
print("This line will run")
challenge icon

Challenge

Beginner

Fix the code so that only Hello, Lua! is printed.

  • Replace the ? with the symbols that turn a line into a comment
  • The line printing Goodbye! should become a comment so it does NOT run
  • Only change the line that starts with ?

Cheat sheet

Comments in Lua:

  • Notes for humans - Lua ignores them
  • Can disable code temporarily without deleting it

Single-line comment:

-- This is a comment
print("Hello!") -- Comment after code

Multi-line comment:

--[[
This is a
multi-line comment
]]

Disabling code:

-- print("This will NOT run")
print("This will run")

Try it yourself

-- Type your code below
? print("Goodbye!")
print("Hello, Lua!")
quiz iconTest yourself

This lesson includes a short quiz. Start the lesson to answer it and track your progress.

All lessons in Fundamentals

1Introduction

The LanguageHello World!Comments

4Operators 2 Relational & Logic

Equality OperatorsRelational OperatorsThe 'and' OperatorThe 'or' OperatorThe 'not' OperatorShort-Circuit EvaluationTruthy and Falsy ValuesRecap - Simple Logic

7Basic Conditional Logic

The if-then StatementThe if-then-else StatementThe elseif StatementRecap - Treasure Chest

10Tables Part 1: List-Style

What is a Table?Creating a TableAccessing Elements by IndexModifying Elements by IndexThe Length Operator '#'table.insert()table.remove()Recap - Manage Party Members

13Project: Simple Potion Shop

Project SetupAdding a PotionProject lessonDisplaying the InventoryProject lessonCalculating Total Stock ValueProject lessonFinding a Specific PotionProject lessonSelling a PotionProject lesson

2Variables and Data Types

What is a Variable?NumbersStringsBooleansThe Value 'nil'The type() FunctionNaming ConventionsRecap - Character Profile

5Basic Output

Printing LiteralsPrinting VariablesPrinting Multiple ValuesCombining Strings & VariablesThe tostring() FunctionInputCastRecap - Status ReportRecap - Till 120

8String Manipulation Basics

string.len()string.upper & string.lowerstring.sub()string.rep()string.find()Recap - Format Username

11Tables 2: Dictionary-Style

Key-Value PairsCreating Dictionary-Style TablAccessing - Bracket NotationAccessing with Dot NotationAdding and Modifying PairsRemoving Pairs with nilRecap - Item Properties

14Variable Scope

Global VariablesLocal VariablesWhy Use Local Variables?Scope and BlocksRecap - Scope Puzzle

3Operators 1 Arithmetic & Conc

Arithmetic OperatorsModulo OperatorExponentiation OperatorString ConcatenationOperator PrecedenceRecap - Simple Calculations

6Project: Character Stats Disp

Welcome MessageDeclare Character StatsProject lessonDisplay Basic StatsProject lessonAdd a Boolean FlagProject lessonFinal SummaryProject lesson

9Functions Basics

Declaring a FunctionCalling a FunctionFunctions with ParametersFunctions with Multiple ParamsThe 'return' StatementRecap - Area Calculator

12Loops Basics

The while LoopThe repeat-until LoopThe Numeric for Loopfor Loop with a StepThe 'break' StatementRecap - Countdown

15Final Challenges

Recap - Player TurnRecap - Simple DatabaseRecap - Sum of Even Numbers