Home Backend Development PHP Tutorial PHP中的符号 ->、=> 和 ::

PHP中的符号 ->、=> 和 ::

Jun 23, 2016 pm 01:23 PM

没关系,下面我们做一下详细的解释,如果你有C++,Perl基础,你会发现这些家伙和他们里面的一些符号功能是差不多的。

‘- >’符号是“插入式解引用操作符”(infix dereference operator)

换句话说,它是调用由引用传递参数的子程序的方法(当然,还有其它的作用)。正如我们上面所提到的,在调用PHP的函数的时候,大部分参数都是通过引用传递的。PHP中的‘->’功能就和它们在Perl或C++中一样。下面是一个简单的解引用的例子:

  echo $x->def(); # 输出

  

  在PHP的脚本中‘=>’操作符时很常见的。因为php数组函数很丰富,我们要经常用到数组,因为它操作数据很方便。

  $phparr= new array( in => 'reply,'

  side => 'left',

  padx => 2m,

  pady => 2m,

  ipadx => 2m,

  ipady => 1m

  )

  顺便说一下,如果你需要用数字“大于等于”的符号,你应该用“>=”而不是“=>”。

     在PHP中“::”这个叫范围解析操作符,又名域运算符  

     “::”符号可以认为是与C语言中的“.”相似的,而它更像C++中(Perl)的::类范围操作符。

      php调用类的内部静态成员,或者是类之间调用就要用::

    下面是一个例子:

      class A

   {

       static $count = 0;

        static function haha()

       {

           //

        }  

       function diaoyoug()

     {

          self::haha();

        self::$count;

       }

   }

  a.b.c; /* C语言中的 */

  a::b::c(); // C++ 中的函数

  $a::b::c; # Perl 5中的标量


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