php 常用的接口和函数

ArrayAccess

— interface to provide accessing to objects as arrays 提供以数组形式访问对象的接口。

interface synopsis 接口需要实现下面几个方法

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

basic usage 基础用法 实现访问数组的方式访问接口

<?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);
?>

the above example will output something similar to : 输出结果

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))

php官网ArrayAccess