Lua Decision Making

In Lua, you can control your program's flow using if, elseif, and else statements, along with logical operators like and, or, and not. These tools help your code make decisions based on different conditions, making your programs smarter and more flexible.

In this article, we'll cover the basics of decision-making in Lua, with simple examples and tips to help you write better code.

Lua if Statement

The if statement is the most basic conditional structure in Lua, used to execute a block of code if a condition is true. It is essential for making simple decisions based on a single condition.

Syntax

if condition then
    -- code to execute if condition is true
end

local age = 20
if age >= 18 then
    print("You are eligible to vote.")
end

Output

You are eligible to vote.

Lua if-else Statement

The if-else statement allows your program to execute specific blocks of code based on the evaluation of conditions, enabling dynamic decision-making within your scripts.

Syntax

if condition then
    -- code to execute if condition is true
else
    -- code to execute if condition is false
end

local temperature = 25
if temperature > 30 then
    print("It's hot outside.")
else
    print("The weather is pleasant.")
end

Output

The weather is pleasant.

elseif for Multiple Conditions in Lua

The if-elseif-else ladder provides a structured approach to evaluate multiple conditions sequentially, executing the corresponding block of code for the first condition that evaluates to true.

Syntax

if condition1 then
    -- code to execute if condition1 is true
elseif condition2 then
    -- code to execute if condition2 is true
else
    -- code to execute if none of the above conditions are true
end

local score = 85
if score >= 90 then
    print("Grade: A")
elseif score >= 80 then
    print("Grade: B")
elseif score >= 70 then
    print("Grade: C")
else
    print("Grade: D")
end

Output

Grade: B

Nested if Statements for Complex Logic

Nested if statements allow you to evaluate multiple conditions in a hierarchical manner, executing code blocks based on complex decision trees.

local age = 25
local has_license = true
if age >= 18 then
    if has_license then
        print("You can drive a car.")
    else
        print("You need a driver's license.")
    end
else
    print("You are too young to drive.")
end

Output

You can drive a car.

Logical Operators in Lua

Logical operators are fundamental tools that enable you to perform boolean operations, facilitating decision-making and control flow within your programs.

• and: Returns true if both conditions are true.​
• or: Returns true if at least one condition is true.​
• not: Reverses the truth value of a condition.

local age = 20
local has_ticket = true
if age >= 18 and has_ticket then
    print("You can enter the concert.")
else
    print("Access denied.")
end

Output

You can enter the concert.

Best Practices for Writing Conditional Logic in Lua

• Use Local Variables: Always declare variables using local inside conditionals to avoid unintended global variables.
• Avoid Deep Nesting: Too many nested if statements can make your code hard to maintain. Use logical operators or helper functions to simplify conditions.
• Readable Code: Proper indentation and comments can make your decision-making logic easier to follow.