如何从一类中获取常量，但不包括可能从父代派生的所有常量? [英] how to get constants from a class excluding all constants that may have been descended from parents?

问题描述

在第二个示例中，PDO用其常量填充MyClass，如何将其过滤掉?

here in second example PDO is populating MyClass with it's constants, how to filter them out ?

class MyClass {
  const PARAM_1 = 1;
  const PARAM_2 = 2;
  const PARAM_3 = 4;

  function MyMethod() {
    $reflector = new ReflectionClass(__CLASS__);
    print_r($reflector->getConstants());
  }

}

$myInstance = new MyClass();
$myInstance->MyMethod();

//returns:
//Array
//(
//    [PARAM_1] => 1
//    [PARAM_2] => 2
//    [PARAM_3] => 4
//)

class MyClassPDO extends PDO {
  const PARAM_1 = 1;
  const PARAM_2 = 2;
  const PARAM_3 = 4;

  function MyMethod() {
    $reflector = new ReflectionClass(__CLASS__);
    print_r($reflector->getConstants());
  }

}

$myInstancePDO = new MyClassPDO('sqlite::memory:');
$myInstancePDO->MyMethod();

//Array
//(
//    [PARAM_1] => 1
//    [PARAM_2] => 2
//    [PARAM_3] => 4
//    [PARAM_BOOL] => 5
//    [PARAM_NULL] => 0
//    [PARAM_INT] => 1
//    [PARAM_STR] => 2
//    [PARAM_LOB] => 3
//    [PARAM_STMT] => 4
//    [PARAM_INPUT_OUTPUT] => -2147483648
//    [PARAM_EVT_ALLOC] => 0
//    [PARAM_EVT_FREE] => 1
//    [PARAM_EVT_EXEC_PRE] => 2
//....and so on

推荐答案

AFAIK

function MyMethod() {
  $reflector = new ReflectionClass(__CLASS__);
  print_r(array_diff($reflector->getConstants(),$reflector->getParentClass()->getConstants()));
}

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