What is the meaning of a parameter in a method before it? For example, in this code publicfunctionupdate (Observable $ _ observable) {$ _ observable, what is the meaning of the Observable before, and what is the role of the novice for help! ------ Solution -------------------- it means that the final parameter must be an instance object of the Observable class. What is the meaning of a parameter in a method before it?
For example, this code public function update (Observable $ _ observable ){
$ _ What is the meaning and function of the observable in front of the Observable?
Help!
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This parameter must be an instance object of the Observable class.
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Variable names are random, except that the passed parameters must be Observable objects. Because PHP is weak, only the specified array and Object types are supported.
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Http://php.net/manual/zh/language.oop5.typehinting.php
