Opereta ya Uchimbaji Salama katika OOP katika PHP

Opereta ya uchimbaji salama ?-> inaruhusu kufikia kwa usalama mbinu na sifa za vitu ambavyo vinaweza kuwa null.

Tuangalie kwa mfano. Tuchukulie tuna darasa lifuatalo:

<?php
	class User
	{
		public $name;
		
		public function __construct($name)
		{
			$this->name = $name;
		}
	}
?>

Tutengeneze kitu cha darasa hili:

<?php
	$user = new User('john');
?>

Tutoe thamani ya sifa yake:

<?php
	$user = new User('john');
	echo $user->name;
?>

Tuchukulie sasa imetokea hivyo, kwamba badala ya kitu tunakuwa na null. Katika hali hii jaribio la kufikia jina la mtumiaji litasababisha hitilafu:

<?php
	$user = null;
	echo $user->name; // hitilafu
?>

Ili kuzuia hitilafu, tunaweza kutumia opereta ya uchimbaji salama:

<?php
	$user = null;
	echo $user?->name;
?>

Boresha msimbo ufuatao kupitia opereta ya uchimbaji salama:

<?php
	class Employee {
		public $name;
		public $salary;
		
		public function __construct($name, $salary)
		{
			$this->name = $name;
			$this->salary = $salary;
		}
	}
	
	$employee = new Employee('john', 1000);
	
	echo $employee->name;
	echo $employee->salary;
?>