Online PHP editor | refs for GDOuR

<?php interface ArrayAccessInterface extends ArrayAccess { public function keyExists(string $offset): bool; public function offsetIsset(string $offset): bool; } abstract class ArrayAccessAbstract implements ArrayAccessInterface { public function offsetExists($offset): bool { return static::offsetIsset((string) $offset); } } class C extends ArrayAccessAbstract { public $data = array( "foo" => null ); public function keyExists(string $offset): bool { return array_key_exists($offset, $this->data); } public function offsetIsset(string $offset): bool { return isset($this->data[$offset]); } public function offsetGet($offset) { return $this->data[$offset]; } public function offsetSet($offset, $value): void { $this->data[$offset] = $value; } public function offsetUnset($offset): void { unset($this->data[$offset]); } } $o = new C(); var_dump(empty($o['foo'])); var_dump(isset($o['foo'])); var_dump($o->keyExists('foo')); var_dump(property_exists($o, 'foo')); #var_dump(array_key_exists('foo', $o)); #var_dump(array_key_exists('foo', ['foo' => null]));