📊 PHP 8.x Comparison Cheat Sheet

Operator ==

Operator ===

Operator <

Operator >

Operator <=

Operator >=

Operator <=>

🔍 in_array() without strict mode

🔀 Sorting behavior (SORT flags)

Sorting flag SORT_REGULAR

Sorting flag SORT_NUMERIC

Sorting flag SORT_STRING

Sorting flag SORT_NATURAL

📅 DateTime objects

$past   = new DateTime('2023-01-01');
$now    = new DateTime('2024-01-01');
$future = new DateTime('2025-01-01');

$past < $now     → true
$future > $now   → true
$now <= $now     → true

$date1 = new DateTime('2024-06-15 10:30:00');
$date2 = new DateTime('2024-06-15 10:30:00');  // same time, different object
$date3 = $date1;                               // same reference

$date1 == $date2   → true  // ✅ same timestamp
$date1 === $date2  → false // ❌ different objects
$date1 === $date3  → true  // ✅ same reference

$mutable   = new DateTime('2024-03-15 12:00:00');
$immutable = new DateTimeImmutable('2024-03-15 12:00:00');

$mutable == $immutable   → true  // ✅ same timestamp

🔧 Closures and first-class callables

$trim1   = trim(...);
$trim2   = trim(...);
$strlen1 = strlen(...);

$trim1 == $trim2      → true   // ✅ same function
$trim1 == $strlen1    → false  // ❌ different functions
$trim1 === $trim2     → false  // ❌ different objects

$closure1 = fn($x) => $x * 2;
$closure2 = fn($x) => $x * 2;   // identical code
$closure3 = $closure1;          // same reference

$closure1 == $closure2   → false  // ❌ different closure objects
$closure1 === $closure2  → false  // ❌ different objects
$closure1 === $closure3  → true   // ✅ same reference

class MyClass {
	public function myMethod() {}
}

$objA = new MyClass;
$objB = new MyClass;

$methodA1 = $objA->myMethod(...);
$methodA2 = $objA->myMethod(...);
$methodB  = $objB->myMethod(...);

$methodA1 == $methodA2   → true   // ✅ same object, same method
$methodA1 == $methodB    → false  // ❌ different object instances
$methodA1 === $methodA2  → false  // ❌ different closure objects