PHP: Is there opposite of null coalescing operator?

As of PHP 8, there is the nullsafe operator ?->. With it you could refactor your code like this:

// @var User|null $user $data['id_user'] = $user?->getId(); 

Prior to PHP 8, you could utilize automatic bool converting to take advantage of the fact that, when converting to bool, null is considered false, but other objects are not (except apparently SimpleXML objects created from empty tags are also considered false). So you could shorten your example to the following:

// @var User|null $user $data['id_user'] = $user ? $user->getId() : null; 

However, this might be less readable since the ? might imply to some people you are working with a bool to begin with, or it could make the reader have to think about how null gets converted to bool. Your original code is more explicit, and thus potentially more readable. In order to make brains work less hard, I often at least consider avoiding using "not equals" whenever possible, and just go with a straight "equals". So you could refactor your code to be like this:

// @var User|null $user $data['id_user'] = $user === null ? null : $user->getId(); 

In this particular case, I think that trick (avoiding "not equals") works fairly well, but sometimes counterintuitively, the code is still more naturally readable to just use a "not equals" anyways.

If you define a __toString() class in your user object, and have that return the id, then you can use the null coalesce operator:

class User { public function __toString() { return (string) $this->getId(); } } $data['id_user'] = $user ?? null; 

This will not generate any warnings either.

However, it doesn't help too much if you have more than one field you want to do this with.