How to copy an object array in php

With the continuous popularity of PHP as an excellent back-end language, its application scope is becoming more and more extensive. The object array in PHP is a very common data type. In actual development, we often need to Object array is assigned or copied. This article will introduce how to copy an object array in PHP, hoping to help PHP developers better process object arrays.

1. Definition of object array

Object array is a data type that stores objects in an array. In PHP, an object can be a single instance or an instance of a class. Putting an object into an array can achieve the purpose of storing and operating multiple objects, which is very convenient for processing complex data structures.

2. Copying object arrays

In PHP, there are two methods for copying object arrays: shallow copy and deep copy.

1. Shallow copy

Shallow copy is to copy an object array so that the new array and the original array refer to the same object. This means that if an object is modified in either array, the corresponding object in the other array will also be modified. The syntax of shallow copy is as follows:

$new_array = $original_array;

Use the above code to assign an object array to another array.

2. Deep copy

Deep copy is to copy an object array, and all objects contained in it are newly created. This means that if you modify an object in one of the arrays, the corresponding objects in the other arrays will not be affected. The syntax of deep copy is as follows:

$new_array = unserialize(serialize($original_array));

By serializing and re-deserializing the original array into a new array, deep copying of all objects can be achieved, and the two arrays are completely independent at this time.

3. Example of object array

The following is a simple object array example:

class Fruit {
  public $name;
  public $color;

  public function __construct($name, $color) {
    $this->name = $name;
    $this->color = $color;
  }
}

$fruits = array(
  new Fruit('apple', 'red'),
  new Fruit('banana', 'yellow')
);

Using shallow copy technology, we can assign the $fruits array to the $new_fruits array Medium:

$new_fruits = $fruits;

Now modify one of the objects and see what happens:

$new_fruits[0]->name = 'orange';

echo $fruits[0]->name; //输出orange
echo $new_fruits[0]->name; //输出orange

Due to the shallow copy, the $new_fruits array and the $fruits array point to the same object, so modifying one will influence another.

Now use deep copy technology:

$new_fruits = unserialize(serialize($fruits));

Modify an object:

$new_fruits[0]->name = 'orange';

echo $fruits[0]->name; //输出apple
echo $new_fruits[0]->name; //输出orange

Due to deep copy, the objects in the two arrays are independent, so modifying one will not affect another.

4. Summary

In PHP, object array is a very practical data type that can easily store and operate multiple objects. When copying an object array, we can use shallow copy or deep copy. A shallow copy causes the new array to reference the same objects as the original array, while a deep copy copies all objects to create a brand new array. I hope this article can bring some help to PHP developers.

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