ArrayAccess（数组式访问）接口

ArrayAccess（数组式访问）接口

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简介

提供像访问数组一样访问对象的能力的接口。 

接口摘要

ArrayAccess {

/* 方法 */

abstract public boolean offsetExists( mixed $offset)

abstract public mixed offsetGet( mixed $offset)

abstract public void offsetSet( mixed $offset, mixed $value)

abstract public void offsetUnset( mixed $offset)

}

Example #1 Basic usage

<?php

class obj implements arrayaccess {

    private $container = array();

    public function __construct() {

        $this->container = array(

            "one"   => 1,

            "two"   => 2,

            "three" => 3,

        );

    }

    public function offsetSet($offset, $value) {

        if (is_null($offset)) {

            $this->container[] = $value;

        } else {

            $this->container[$offset] = $value;

        }

    }

    public function offsetExists($offset) {

        return isset($this->container[$offset]);

    }

    public function offsetUnset($offset) {

        unset($this->container[$offset]);

    }

    public function offsetGet($offset) {

        return isset($this->container[$offset]) ? $this->container[$offset] : null;

    }

}

$obj = new obj;

var_dump(isset($obj["two"]));

var_dump($obj["two"]);

unset($obj["two"]);

var_dump(isset($obj["two"]));

$obj["two"] = "A value";

var_dump($obj["two"]);

$obj[] = 'Append 1';

$obj[] = 'Append 2';

$obj[] = 'Append 3';

print_r($obj);

?>  

以上例程的输出类似于：

bool(true)

int(2)

bool(false)

string(7) "A value"

obj Object

(

    [container:obj:private] => Array

        (

            [one] => 1

            [three] => 3

            [two] => A value

            [0] => Append 1

            [1] => Append 2

            [2] => Append 3

        )

)

Table of Contents

◾ArrayAccess::offsetExists — 检查一个偏移位置是否存在

◾ArrayAccess::offsetGet — 获取一个偏移位置的值

◾ArrayAccess::offsetSet — 设置一个偏移位置的值

◾ArrayAccess::offsetUnset — 复位一个偏移位置的值