PHP8.1 update: deep cloning of arrays and objects

PHP8.1 Update: Deep Cloning of Arrays and Objects

With the release of PHP8.1 version, many new features and updates have been introduced. One very useful update concerns deep cloning of arrays and objects. Previously, when cloning an array or object, only their reference was cloned rather than creating a completely new copy. This can lead to some unexpected side effects and bugs. But in PHP8.1, we can use the new clone operator to achieve deep cloning.

In previous PHP versions, we usually used recursive functions to achieve deep cloning. But this approach can cause performance issues, especially when dealing with large, complex arrays or objects. In PHP8.1, we can improve performance and simplify code through the new clone operator.

The following is an example that shows how to use the new clone operator to deeply clone an array in PHP8.1:

$array = [
    'name' => 'John',
    'age' => 30,
    'address' => [
        'city' => 'New York',
        'country' => 'USA'
    ]
];

$cloneArray = clone $array;

// 修改克隆后的数组
$cloneArray['name'] = 'Jane';
$cloneArray['address']['city'] = 'Los Angeles';

// 输出原始数组
print_r($array);

// 输出克隆后的数组
print_r($cloneArray);

In the above example, we first create an array containing the nested Primitive array of sets of arrays. Then, use the clone operator to deeply clone the original array into another variable $cloneArray. Next, we modify the values ​​in the cloned array and observe whether the original array is affected.

Run the above code, the output result is as follows:

Array
(
    [name] => John
    [age] => 30
    [address] => Array
        (
            [city] => New York
            [country] => USA
        )

)
Array
(
    [name] => Jane
    [age] => 30
    [address] => Array
        (
            [city] => Los Angeles
            [country] => USA
        )

)

As can be seen from the output result, the original array is not affected. The cloned array can be modified independently.

It is also very simple to use the new clone operator to perform deep cloning of objects. The following is a sample code:

class Person
{
    public $name;
    public $age;
    public $address;
}

$person = new Person();
$person->name = 'John';
$person->age = 30;
$person->address = new stdClass();
$person->address->city = 'New York';
$person->address->country = 'USA';

$clonePerson = clone $person;

// 修改克隆后的对象
$clonePerson->name = 'Jane';
$clonePerson->address->city = 'Los Angeles';

// 输出原始对象
print_r($person);

// 输出克隆后的对象
print_r($clonePerson);

In the above example, we created an object $person of the Person class and set some properties. Then, use the clone operator to deeply clone the object into another object $clonePerson. Modify the properties of the cloned object and observe whether the original object is affected.

Run the above code, the output result is as follows:

Person Object
(
    [name] => John
    [age] => 30
    [address] => stdClass Object
        (
            [city] => New York
            [country] => USA
        )

)
Person Object
(
    [name] => Jane
    [age] => 30
    [address] => stdClass Object
        (
            [city] => Los Angeles
            [country] => USA
        )

)

Similarly, the original object is not affected, and the cloned object can be modified independently.

In PHP8.1, deep cloning of arrays and objects becomes simpler and more efficient using the new clone operator. No more need to use recursive functions or other complex methods to achieve deep cloning. This greatly improves developer productivity and code readability.

However, it should be noted that deep cloning can only take effect when the properties of the array or object are basic data types or scalar types. If the property is a reference type, such as a resource or other object, you need to handle it yourself.

To sum up, the update of PHP8.1 brings in-depth cloning function of arrays and objects, making the cloning process easier and more efficient through the new cloning operator. Developers can handle complex data structures more easily, improving code reliability and performance.

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