Array functions in PHP8: efficient application method of array_intersect_key()

Array function in PHP8: efficient application method of array_intersect_key()

In the PHP programming language, array is a very important data type. When working with arrays, developers often need to use array functions to accomplish certain tasks. The new function array_intersect_key() in PHP8 can be used to compare multiple arrays and return the value corresponding to the same key. This article will show you how to use the array_intersect_key() function to outline efficient application scenarios.

Introduction to the array_intersect_key() function

The array_intersect_key() function is to compare two or more arrays and return an array containing the keys and values ​​that are present in all input arrays . The syntax of the function is as follows:

array array_intersect_key(array $array1, array $array2 [, array $... ])

Among them, $array1 and $array2 refer to the two arrays passed in, and the following optional arrays refer to any number of additional arrays. The function will compare the keys of all arrays and return a new array containing the keys and their corresponding values ​​​​that exist in all arrays.

Use the array_intersect_key() function to view the intersection of two arrays

The following example will demonstrate how to use the array_intersect_key() function to view the intersection between two arrays:

$array1 = array('a' => 'red', 'b' => 'green', 'c' => 'blue');
$array2 = array('a' => 'red', 'b' => 'blue', 'd' => 'orange');

$result = array_intersect_key($array1, $array2);
print_r($result);

The execution result will display the following information:

Array
(
    [a] => red
)

In the example, we define two arrays $array1 and $array2, and then use the array_intersect_key() function to compare their key names. The result returned by the function is the key name and the corresponding value included in both arrays, that is, there is only one entry of 'a => red'. This function is a very fast operation and can therefore be widely used in PHP programs.

Use the array_intersect_key() function to view the intersection of multiple arrays

In addition to comparing two arrays, the array_intersect_key() function can also compare the intersection between multiple arrays. The following example will demonstrate how to use a function to compare the intersection of key names between three arrays:

$array1 = array('a' => 'red', 'b' => 'green', 'c' => 'blue');
$array2 = array('a' => 'red', 'b' => 'blue', 'd' => 'orange');
$array3 = array('a' => 'red', 'b' => 'green', 'e' => 'yellow');

$result = array_intersect_key($array1, $array2, $array3);
print_r($result);

The execution result will display the following information:

Array
(
    [a] => red
    [b] => green
)

In this example, we define three arrays $array1, $array2, and $array3, and then use the array_intersect_key() function to compare their key names. The result returned by the function is the key name and the corresponding value included in the three arrays, that is, there are two entries 'a => red' and 'b => green'. Unlike comparing the intersection of two arrays, comparing the intersection of multiple arrays may take more time to complete, so you should be very careful when dealing with large amounts of data to avoid overloading your program.

Use the array_intersect_key() function to compare objects

In PHP8, we can also use the array_intersect_key() function to compare objects. In this case, the array keys will be the object's property names, and the corresponding values ​​will be the property values. The following example demonstrates how to use the array_intersect_key() function to compare key intersections between two objects:

class MyClass {
    public $a = 'red';
    private $b = 'green';
    protected $c = 'blue';
}

$obj1 = new MyClass();
$obj2 = new MyClass();
$obj2->a = 'blue';
$obj2->d = 'orange';

$result = array_intersect_key(get_object_vars($obj1), get_object_vars($obj2));
print_r($result);

When you run this example, you will see the following output:

Array
(
    [a] => red
)

In this example, we define two instances of the MyClass class $obj1 and $obj2 and use the array_intersect_key() function to compare their properties. The result returned by the function is the attribute name and corresponding value included in both objects, that is, there is only one entry of 'a => red'. It should be noted that this function can only compare the properties of objects, not the methods of objects.

Summary

In this article, we introduced you to the usage of the new array function array_intersect_key() in PHP8. We demonstrated how to compare the intersection of keys between two or more arrays and showed you efficient uses of this function. We also demonstrated how this function can be applied to compare the intersection of property names between two objects, where the object's property names are the keys of an array. When developing PHP8 applications, using the array_intersect_key() function can make coding simpler, faster and more efficient.

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