ArrayAccess(数组式访问)接口

(PHP 5, PHP 7, PHP 8)

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

interface ArrayAccess {
/* 方法 */
public offsetExists(mixed $offset): bool
public offsetGet(mixed $offset): mixed
public offsetSet(mixed $offset, mixed $value): void
public offsetUnset(mixed $offset): void
}

示例

示例 #1 基础用法

<?php
class Obj implements ArrayAccess {
public
$container = [
"one" => 1,
"two" => 2,
"three" => 3,
];

public function
offsetSet($offset, $value): void {
if (
is_null($offset)) {
$this->container[] = $value;
} else {
$this->container[$offset] = $value;
}
}

public function
offsetExists($offset): bool {
return isset(
$this->container[$offset]);
}

public function
offsetUnset($offset): void {
unset(
$this->container[$offset]);
}

public function
offsetGet($offset): mixed {
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);
?>

以上示例的输出类似于:

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
        )

)

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