為什么類里沒有name這個屬性，$car->name = '汽車';還能運行

class?Car?{
????private?$ary?=?array();
????
????public?function?__set($key,?$val)?{
????????$this->ary[$key]?=?$val;
????}
????
????public?function?__get($key)?{
????????if?(isset($this->ary[$key]))?{
????????????return?$this->ary[$key];
????????}
????????return?null;
????}
????
????public?function?__isset($key)?{
????????if?(isset($this->ary[$key]))?{
????????????return?true;
????????}
????????return?false;
????}
????
????public?function?__unset($key)?{
????????unset($this->ary[$key]);
????}
}
$car?=?new?Car();
$car->name?=?'汽車';??//name屬性動態(tài)創(chuàng)建并賦值
echo?$car->name;

DimensionPlane

2018-07-27

源自：PHP進階篇 2-9

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2 回答

Mayukiii73
2019-01-03

public?function?__set($key,?$val)
就是用魔術(shù)函數(shù)?__set?動態(tài)創(chuàng)建給私有成員屬性設(shè)置值的,這里有兩個參數(shù),一個是參數(shù)的名稱,一個是參數(shù)的值
而動態(tài)創(chuàng)建產(chǎn)生的對象屬性是全局的并且無需聲明就可以訪問,所以當(dāng)用$car?=?new?Car();?$car->name?=?'汽車';
調(diào)用這個類和方法的時候,就是給$key和$val賦值了name和'汽車',所以當(dāng)你echo的時候就會輸出'汽車'