我必须检查ArrayCollection中是否已存在Email实体,但我必须将电子邮件检查为字符串(实体包含ID以及与其他entites的某些关系,因此我使用单独的表来保留所有电子邮件).
现在,在第一次我写了这段代码：
/**
* A new Email is adding: check if it already exists.
*
* In a normal scenario we should use $this->emails->contains().
* But it is possible the email comes from the setPrimaryEmail method.
* In this case,the object is created from scratch and so it is possible it contains a string email that is
* already present but that is not recognizable as the Email object that contains it is created from scratch.
*
* So we hav to compare Email by Email the string value to check if it already exists: if it exists,then we use
* the already present Email object,instead we can persist the new one securely.
*
* @var Email $existentEmail
*/
foreach ($this->emails as $existentEmail) {
if ($existentEmail->getEmail()->getEmail() === $email->getEmail()) {
// If the two email compared as strings are equals,set the passed email as the already existent one.
$email = $existentEmail;
}
}
但是阅读ArrayCollection类我看到了方法exists,这似乎是我做同样事情的一种更加优雅的方式.
但我不知道如何使用它：有人可以解释我如何使用这个方法给出上面的代码？
当然,在PHP中,Closure是一个简单的
Anonymous functions.您可以重写您的代码如下：
$exists = $this->emails->exists(function($key,$element) use ($email){
return $email->getEmail() === $element->getEmail()->getEmail();
}
);
希望这有帮助