Operators & Expressions ➕

Master PHP's arithmetic, comparison, logical, and string operators — including the spaceship and null coalescing operators.

What You'll Learn in This Lesson

• Arithmetic operators: +, -, *, /, %, ** (exponentiation)
• The critical difference between == (loose) and === (strict)
• PHP 7+ operators: spaceship <=> and null coalescing ??
• Logical operators: &&, ||, ! for combining conditions
• String concatenation with the . (dot) operator

Note: PHP runs on a server. Our examples simulate PHP logic using JavaScript. To run real PHP, install PHP.

🎯 Real-World Analogy: Operators are like tools in a toolbox. Arithmetic operators are your calculator, comparison operators are your measuring tape (checking if things are equal or bigger), and logical operators are decision-making switches (if this AND that, do something).

1️⃣ Operator Categories

Category	Operators	Example
Arithmetic	+ - * / % **	$a + $b
Assignment	= += -= *= /= .=	$x += 5
Comparison	== === != !== < > <=>	$a === $b
Logical	&& \|\| ! and or	$a && $b
String	. .=	"Hi " . $name
Null Coalescing	?? ??=	$x ?? "default"

Try It: Arithmetic & String Operators

Practice arithmetic, assignment, increment/decrement, and string concatenation

Try it Yourself »

JavaScript

// PHP Operators (simulated in JavaScript)
console.log("=== Arithmetic Operators ===");
console.log();

let a = 15;
let b = 4;

console.log("$a = " + a + ", $b = " + b);
console.log();
console.log("$a + $b  = " + (a + b) + "   (Addition)");
console.log("$a - $b  = " + (a - b) + "  (Subtraction)");
console.log("$a * $b  = " + (a * b) + "  (Multiplication)");
console.log("$a / $b  = " + (a / b) + " (Division — returns float!)");
console.log("$a % $b  = " + (a % b) + "   (Modulus — remainder)");
co
...

Try It: Comparison & Logical Operators

Learn the crucial difference between == and ===, plus PHP 7+ operators

Try it Yourself »

JavaScript

// PHP Comparison & Logical Operators
console.log("=== Comparison Operators ===");
console.log();

// The crucial difference: == vs ===
console.log("IMPORTANT: == (loose) vs === (strict)");
console.log();

console.log("  0 == false    → " + (0 == false) + "    (loose: type juggling!)");
console.log('  0 === false   → ' + (0 === false) + "   (strict: different types)");
console.log();
console.log('  "5" == 5      → ' + ("5" == 5) + "    (loose: string converted)");
console.log('  "5" === 5     → 
...

⚠️ Common Mistakes

⚠️

Using == instead of === — 0 == "hello" is true in PHP! Always prefer ===.

⚠️

Using + for strings — PHP uses . for concatenation. "5" + "3" equals 8 (numeric addition!).

⚠️

Confusing = with == — if ($x = 5) assigns 5 to $x (always true). Use == or === for comparison.

💡

Pro Tip: Use ?? (null coalescing) instead of isset() checks — it's cleaner and more readable.

📋 Quick Reference — PHP Operators

Operator	Meaning	Example
===	Strict equal	$a === $b
<=>	Spaceship (3-way)	$a <=> $b → -1/0/1
??	Null coalescing	$x ?? "default"
.	String concat	"Hi " . $name
**	Exponentiation	2 ** 10 → 1024

🎉 Lesson Complete!

You've mastered PHP operators! Next, learn how to control program flow with if/else and switch statements.