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為什么類(lèi)里沒(méi)有name這個(gè)屬性，$car->name = '汽車(chē)';還能運(yùn)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();
$car->name?=?'汽車(chē)';??//name屬性動(dòng)態(tài)創(chuàng)建并賦值
echo?$car->name;

DimensionPlane

2018-07-27

源自：PHP進(jìn)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(dòng)態(tài)創(chuàng)建給私有成員屬性設(shè)置值的,這里有兩個(gè)參數(shù),一個(gè)是參數(shù)的名稱(chēng),一個(gè)是參數(shù)的值
而動(dòng)態(tài)創(chuàng)建產(chǎn)生的對(duì)象屬性是全局的并且無(wú)需聲明就可以訪問(wèn),所以當(dāng)用$car?=?new?Car();?$car->name?=?'汽車(chē)';
調(diào)用這個(gè)類(lèi)和方法的時(shí)候,就是給$key和$val賦值了name和'汽車(chē)',所以當(dāng)你echo的時(shí)候就會(huì)輸出'汽車(chē)'