为什么[]表示法用于将元素输入到静态数组[复制]

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This question already has an answer here:

• Reference — What does this symbol mean in PHP? 18 answers

in the original example $methods is a static array.It is used to assign outsider functions as methods to a class.But to input new element to this array writer used the following expression

static protected $methods = array();

i removed the static keyword from the variable declaration and tried to execute the code.

protected  $methods = array();

the execution gave the following error:

Fatal error: Access to undeclared static property: Dynamic::$methods in C:\xampp\htdocs\practice\json.php on line 6

what is this [ ] notation is used for and how it is related to static keyword??

original full code:

class Dynamic {
  static protected $methods = array();

  public static function registerMethod($method) {
    self::$methods[] = $method;
  }

  private function __call($method, $args) {
    if (in_array($method, self::$methods)) {
      return call_user_func_array($method, $args);
    }
  }
}

function test() {
  print "Hello World" . PHP_EOL;
}

Dynamic::registerMethod('test');
$d = new Dynamic();
$d->test();

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Answer 1

what is this [ ] notation is used for and how it is related to static keyword??

The use of static and [] are unrelated.

The code $array[] = $i is a shorthand for pushing the element $i onto the end of the array $array. It could also be written array_push($array, $i).