How to use array_diff function to get the difference set in PHP

In PHP, array is a very common data type, usually used to store a set of related data. In actual development projects, it is often necessary to compare multiple arrays and extract their differences. At this time, you can use the array_diff function in PHP to achieve this.

array_diff function is a function used in PHP to find the difference between two or more arrays. Its specific usage is as follows:

array_diff (array $array1 , array $array2 [, array $... ]) : array

Among them, the parameter $array1 is to be compared. Base array, $array2 is the array to be compared with the base array, and the subsequent parameter $... can continue to pass in other arrays that need to be compared. This function will return all elements that are different from the base array into a new array.

Let’s take a look at how to use the array_diff function to find the difference between two arrays through an example.

<?php
$array1 = array("a" => "apple", "b" => "banana", "c" => "cherry");
$array2 = array("b" => "banana", "c" => "cherry", "d" => "date");

$result = array_diff($array1, $array2);
print_r($result);
?>

The output result of the above code is:

Array
(
    [a] => apple
)

As you can see, since there is only one element "a" in $array1 that is different from $array2, the array_diff function returns only the element "a" new array.

In addition to passing in two arrays, the array_diff function can also pass in multiple arrays for comparison. Let's look at an example of passing in three arrays:

<?php
$array1 = array("a" => "apple", "b" => "banana", "c" => "cherry");
$array2 = array("b" => "banana", "c" => "cherry", "d" => "date");
$array3 = array("b" => "banana");

$result = array_diff($array1, $array2, $array3);
print_r($result);
?>

The output result of the above code is:

Array
(
    [a] => apple
    [c] => cherry
)

As you can see, among the three arrays, there is only the element "a of $array1 " and "c" are different from other arrays, so the array_diff function returns a new array containing these two elements.

It is important to note that the array_diff function compares the key values ​​of the array, not just the values. That is, two elements are considered the same only if their keys and values ​​are the same. If you want to compare only the values ​​of arrays, you can use functions such as array_diff_key, array_diff_assoc, and array_udiff.

In summary, the array_diff function is a function used to compare the differences between multiple arrays and return different elements. For scenarios that require array comparison in PHP, the array_diff function is a very practical tool.

The above is the detailed content of How to use array_diff function to get the difference set in PHP. For more information, please follow other related articles on the PHP Chinese website!