PHP provides a method you can use to copy an object. The method is __clone, with two underscores. You can write your own __clone method in a class if you want to specify statements to run when the object is copied. If you don’t write your own, PHP uses its default __clone method that copies all the properties as is.
For example, you could write the following class:
private $gas = 0;
private $color = “red”;
$this->gas = $this->gas + $amount;
echo “$amount gallons added to gas tank”;
$this->gas = 5;
Using this class, you can create an object and copy it, as follows:
$firstCar = new Car;
$secondCar = clone $firstCar;
After these statements, you have two cars:
The $firstCar is red and contains ten gallons of gas. The ten gallons were added with the addGas method. The $secondCar is red, but contains five gallons of gas. The duplicate car is created using the __clone method in the Car class. This method sets gas to 5 and doesn’t set $color at all.
If you didn’t have a __clone method in the Car class, PHP would use a default __clone method that would copy all the properties, making $secondCar both red and containing ten gallons of gas.