Interception method of php array difference set

PHP is a widely used server-side programming language that has powerful array operation functions, such as array difference. Array difference means to filter out different elements in two arrays and return them as a new array. In actual development, the use of array difference is very common, and how to intercept the array difference is an important skill that PHP developers need to master.

This article will introduce the interception method of PHP array difference set, including examples of using array_diff and array_udiff functions.

array_diff function

The array_diff function can be used to compare the difference between two arrays and return a new array containing values ​​that only exist in the first array.

The following is a sample code that uses the array_diff function to intercept the array difference:

<?php
$array1 = array('a', 'b', 'c', 'd');
$array2 = array('b', 'd', 'e', 'f');
$diff = array_diff($array1, $array2);
print_r($diff);
?>

This code will create two arrays $array1 and $array2, and use the array_diff function to save the values ​​that exist in $array1 Elements that do not exist in $array2 are filtered out and saved to the $diff array. The final output of the $diff array is:

Array
(
    [0] => a
    [1] => c
)

array_udiff function

If you are comparing not only the values ​​in the array but the element objects in the array, you need to use the array_udiff function. The array_udiff function can be used to compare the difference between two arrays and return a new array containing values ​​that only exist in the first array, but users can customize a callback function to implement their own comparison rules.

The following is a sample code that uses the array_udiff function to intercept the array difference:

<?php
class Fruit
{
    public $name;
    public function __construct($name)
    {
        $this->name = $name;
    }
}
function compareFruits($a, $b)
{
    if ($a->name === $b->name) {
        return 0;
    }
    return ($a->name > $b->name) ? 1 : -1;
}
$array1 = array(new Fruit('apple'), new Fruit('orange'), new Fruit('banana'));
$array2 = array(new Fruit('apple'), new Fruit('pear'), new Fruit('banana'));
$diff = array_udiff($array1, $array2, 'compareFruits');
print_r($diff);
?>

This code will create two arrays $array1 and $array2, and use the array_udiff function to save the values ​​that exist in $array1 Elements that do not exist in $array2 are filtered out and saved to the $diff array. The custom callback function compareFruits is used to compare the name attribute of Fruit objects. The final output result of the $diff array is:

Array
(
    [1] => Fruit Object
        (
            [name] => orange
        )

)

Summary

This article introduces the method of using PHP's array_diff and array_udiff functions to intercept the array difference set. In actual development, interception of array difference is a very common operation and a skill that PHP developers must master. By mastering the use of these functions, developers can handle array difference operations more efficiently.

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