PHP Function Parameters

Function parameters make your functions flexible and reusable. Learn about default values, type declarations, and modern PHP 7+ features for safer, more predictable code!

Click Run to execute your code

Default Parameters

<?php
function greet($name = "Guest") {
    return "Hello, $name!";
}

echo greet();         // "Hello, Guest!"
echo greet("Alice");  // "Hello, Alice!"
?>

Type Declarations (PHP 7+)

<?php
function add(int $a, int $b): int {
    return $a + $b;
}

echo add(5, 3);  // 8
?>

Nullable Types (PHP 7.1+)

<?php
function findUser(?string $email): ?array {
    if ($email === null) {
        return null;
    }
    return ["email" => $email];
}
?>

Summary

What's Next?

Next, learn about Variable Functions and anonymous functions (closures)!