1、=>的用法
在php中数组默认键名是整数，也可以自己定义任意字符键名（最好是有实际意义），如：
$css=array(‘style‘=>‘0‘，‘color’=>‘green‘)；
则$css[‘style‘]==‘0‘，$css[‘color‘]==‘green‘。
2、->的用法
->用来引用对象的成员（属性与方法）；
1 <?php 2 ??$arr=[‘a‘=>123,‘b‘=>456];//数组初始化 3 ??echo $arr[‘a‘];//数组引用 4 ??print_r($arr);//查看数组 5 ??class A{ 6 ????public $a=123; 7 ????public $b=456; 8 ??} 9 ??$obj=new A();10 ??echo $obj->a;//对象引用11 ??print_r($obj);//查看对象12 ?>输出结果：
123Array( ???[a] => 123 ???[b] => 456)123A Object( ???[a] => 123 ???[b] => 456)
3、::的用法
双冒号操作符即作用域限定操作符Scope Resolution Operator可以访问静态、const和类中重写的属性与方法。
（1）Program List：用变量在类定义外部访问
1 <?php 2 class Fruit { 3 ????const CONST_VALUE = ‘Fruit Color‘; 4 } 5 ?6 $classname = ‘Fruit‘; 7 echo $classname::CONST_VALUE; // As of PHP 5.3.0 8 ?9 echo Fruit::CONST_VALUE;10 ?>（2）Program List：在类定义外部使用::
1 ???2 <?php 3 class Fruit { 4 ????const CONST_VALUE = ‘Fruit Color‘; 5 } 6 ?7 class Apple extends Fruit 8 { 9 ????public static $color = ‘Red‘;10 11 ????public static function doubleColon() {12 ????????echo parent::CONST_VALUE . "\n";13 ????????echo self::$color . "\n";14 ????}15 }16 17 Apple::doubleColon();18 ?>（3）Program List：调用parent方法
1 <?php 2 class Fruit 3 { 4 ????protected function showColor() { 5 ????????echo "Fruit::showColor()\n"; 6 ????} 7 } 8 ?9 class Apple extends Fruit10 {11 ????// Override parent‘s definition12 ????public function showColor()13 ????{14 ????????// But still call the parent function15 ????????parent::showColor();16 ????????echo "Apple::showColor()\n";17 ????}18 }19 20 $apple = new Apple();21 $apple->showColor();22 ?>（4）Program List：使用作用域限定符
1 ???2 <?php 3 ????class Apple 4 ????{ 5 ????????public function showColor() 6 ????????{ 7 ????????????return $this->color; 8 ????????} 9 ????}10 11 ????class Banana12 ????{13 ????????public $color;14 15 ????????public function __construct()16 ????????{17 ????????????$this->color = "Banana is yellow";18 ????????}19 20 ????????public function GetColor()21 ????????{22 ????????????return Apple::showColor();23 ????????}24 ????}25 26 ????$banana = new Banana;27 ????echo $banana->GetColor();28 ?>（5）Program List：调用基类的方法
1 ?????2 <?php 3 ?4 class Fruit 5 { 6 ????static function color() 7 ????{ 8 ????????return "color"; 9 ????}10 11 ????static function showColor()12 ????{13 ????????echo "show " . self::color();14 ????}15 }16 17 class Apple extends Fruit18 {19 ????static function color()20 ????{21 ????????return "red";22 ????}23 }24 25 Apple::showColor();26 // output is "show color"!27 28 ?>PHP关于=>和->以及::的用法
原文地址：http://www.cnblogs.com/shenzikun1314/p/7467215.html