PHP Quick Reference

<?php
echo "Hello";

$name = "Ada";

$age = 36;

const MAX = 100;

echo $name;

print_r($array);

var_dump($value);

$name = $_GET['name'] ?? 'guest';

$user?->address?->city

is_numeric($x)

(int) "42"

intval("42")

"Hi {$user['name']}, you are $age"

$full = $first . ' ' . $last;

strlen($s)

strtoupper($s)

ucfirst($s)

str_contains($s, 'php')

str_starts_with($s, 'http')

str_replace('a', 'b', $s)

trim($s)

explode(',', $s)

implode(', ', $parts)

sprintf('%.2f', $price)

number_format(1234.5, 2)

htmlspecialchars($input, ENT_QUOTES, 'UTF-8')

$nums = [3, 1, 2];

$nums[] = 4;  // append

$user = ['name' => 'Ada', 'age' => 36];

foreach ($nums as $n) { }

foreach ($user as $key => $value) { }

count($nums)

in_array(3, $nums)

array_key_exists('name', $user)

array_map(fn($n) => $n * 2, $nums)

array_filter($nums, fn($n) => $n > 1)

array_sum($nums)

sort($nums)

usort($users, fn($a, $b) => $a['age'] <=> $b['age'])

array_reverse($nums)

array_merge($a, $b)

array_keys($user)

array_values($user)

[$first, $second] = $nums;

if ($x > 0) {
    // ...
} elseif ($x === 0) {
    // ...
} else {
    // ...
}

$label = match ($status) {
    'ok' => 'Success',
    'err' => 'Failed',
    default => 'Unknown',
};

for ($i = 0; $i < 5; $i++) { }

while ($running) { }

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

function greet(string $name = 'world') { }

greet(name: 'Ada');

$double = fn($n) => $n * 2;

class User {
    public function __construct(
        public string $name,
        private int $age = 0,
    ) {}
}

$u = new User('Ada');

$u->name

class Admin extends User { }

class Dog implements Animal { }

public static function create(): static { }

User::create()

enum Status: string {
    case Active = 'active';
    case Disabled = 'disabled';
}

public readonly string $id;

file_get_contents('in.txt')

file_put_contents('out.txt', $text)

json_encode($data, JSON_PRETTY_PRINT)

json_decode($json, true)

$_GET['q']

$_POST['email']

$_SERVER['REQUEST_METHOD']

session_start();
$_SESSION['user_id'] = 7;

header('Location: /login');
exit;

password_hash($pw, PASSWORD_DEFAULT)

password_verify($pw, $hash)

try {
    risky();
} catch (Exception $e) {
    echo $e->getMessage();
}

php -S localhost:8000