PHP中is_array和is_object的区别

function process_data($data) {
  if (is_array($data)) {
    foreach ($data as $item) {
      // 处理数组中的每个元素
      echo $item . "\n";
    }
  } else {
    echo "Error: Input must be an array.\n";
  }
}

process_data([1, 2, 3]); // 输出 1 2 3
process_data("not an array"); // 输出 Error: Input must be an array.

class MyClass {
  public function sayHello() {
    echo "Hello from MyClass!\n";
  }
}

function greet($obj) {
  if (is_object($obj) && method_exists($obj, 'sayHello')) {
    $obj->sayHello();
  } else {
    echo "Error: Input must be an object with a sayHello method.\n";
  }
}

$myObj = new MyClass();
greet($myObj); // 输出 Hello from MyClass!
greet("not an object"); // 输出 Error: Input must be an object with a sayHello method.

interface MyInterface {
  public function doSomething();
}

class MyClass implements MyInterface {
  public function doSomething() {
    echo "Doing something from MyClass!\n";
  }
}

function process_input($input) {
  if (is_array($input)) {
    echo "Processing array input...\n";
    foreach ($input as $item) {
      echo $item . "\n";
    }
  } elseif (is_object($input) && $input instanceof MyInterface) {
    echo "Processing object input...\n";
    $input->doSomething();
  } else {
    echo "Error: Input must be an array or an object implementing MyInterface.\n";
  }
}

process_input([1, 2, 3]); // 输出 Processing array input... 1 2 3
$myObj = new MyClass();
process_input($myObj); // 输出 Processing object input... Doing something from MyClass!
process_input("not an array or object"); // 输出 Error: Input must be an array or an object implementing MyInterface.