PHP预定义接口：数组式访问
2019-09-07 阅读 : 次
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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 offsetExists ( mixed$offset ) : boolean abstract public offsetGet ( mixed $offset ) : mixed abstract public offsetSet ( mixed $offset , mixed $value ) : void abstract public offsetUnset ( mixed $offset ) : void } 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
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