array_multisort() function in PHP: How to sort multiple arrays

The array_multisort() function in PHP: How to sort multiple arrays requires specific code examples

In PHP development, it is often necessary to sort multiple arrays Sorting, for example, by multiple fields such as age, name, etc. PHP provides the array_multisort() function for sorting multiple arrays. This article will introduce the usage of array_multisort() function and provide specific code examples.

1. Introduction to array_multisort() function

The array_multisort() function is used to sort multiple arrays. This function can sort multiple arrays at the same time, and can also specify the sorting method, including ascending or descending order. The basic syntax is as follows:

bool array_multisort ( array &$array1 [, mixed $array1_sort_order = SORT_ASC [, mixed $array1_sort_flags = SORT_REGULAR [, mixed $... ]]] )

Among them, $array1 represents the first array to be sorted, and the following parameters represent other arrays to be sorted. The $array1_sort_order and $array1_sort_flags parameters represent the sorting method and sorting flags respectively. For specific values, please refer to the PHP manual. The function returns a Boolean value.

2. Array_multisort() function example

The following explains how to use the array_multisort() function through specific examples. Suppose there are two arrays as follows. It needs to be sorted according to the value of the first array, and the second array changes accordingly.

<?php
 
// 待排序数组
$array1 = array(4, 2, 3, 1);
$array2 = array('d', 'b', 'c', 'a');
 
// 对数组进行排序
array_multisort($array1, $array2);
 
print_r($array1);
print_r($array2);
 
?>

The code execution process is as follows:

1. First, define two arrays $array1 and $array2, which respectively represent the arrays to be sorted.
2. Then, call the array_multisort() function to sort the array. Since only two arrays are passed as parameters, it means that only the value of the first array is sorted. The default sorting method is ascending order, and the sorting flag is SORT_REGULAR.
3. Finally, the sorted array content is output, in which the values ​​of $array1 are arranged in ascending order, and the corresponding values ​​in $array2 are also sorted.

The running results are as follows:

Array ( [0] => 1 [1] => 2 [2] => 3 [3] => 4 )
Array ( [0] => a [1] => b [2] => c [3] => d )

It can be seen from the running results that due to the use of the array_multisort() function, the two arrays are sorted according to the value of $array1, while $array2 The values ​​of are also sorted accordingly.

3. More examples of the array_multisort() function

In addition to the above basic examples, the array_multisort() function can also perform more sorting operations. For example, you can limit sorting to descending order, sorting by multiple fields, etc.

Some specific sample codes are provided below for reference:

1. Arranged in descending order

<?php
 
// 待排序数组
$array1 = array(4, 2, 3, 1);
$array2 = array('d', 'b', 'c', 'a');
 
// 对数组进行排序
array_multisort($array1, SORT_DESC, $array2);
 
print_r($array1);
print_r($array2);
 
?>

The code execution process is similar to the above example, the only difference is The difference is that the second parameter specifies descending order.

2. Sort by multiple fields

<?php
 
// 待排序数组
$array1 = array('Tom', 'John', 'Mary', 'Bob');
$array2 = array(20, 30, 25, 35);
$array3 = array(170, 165, 180, 175);
 
// 对数组进行排序
array_multisort($array1, SORT_ASC, $array2, SORT_ASC, $array3, SORT_DESC);
 
print_r($array1);
print_r($array2);
print_r($array3);
 
?>

The code execution process is as follows:

1. Define three arrays $array1, $array2 and $ array3, representing name, age and height respectively.
2. Calling the array_multisort() function to sort the three arrays, first sort them in ascending order according to $array1, then sort them in ascending order according to $array2, and finally sort them in descending order according to $array3.
3. Output the contents of the three sorted arrays.

The running results are as follows:

Array ( [0] => Bob [1] => John [2] => Mary [3] => Tom )
Array ( [0] => 30 [1] => 20 [2] => 25 [3] => 35 )
Array ( [0] => 175 [1] => 170 [2] => 180 [3] => 165 )

It can be seen from the running results that due to the use of multiple fields for sorting, the sorting order of the three arrays are: sorted in ascending order by name, If the names are the same, they are sorted in ascending order of age; if the names and ages are the same, they are sorted in descending order of height.

4. Summary

This article introduces how to use the array_multisort() function in PHP and provides specific code examples. This function can sort multiple arrays at the same time, and can specify ascending or descending order. It also supports multiple fields for sorting operations. In PHP development, the array_multisort() function is a very useful tool, which can greatly simplify development work and improve program performance.

The above is the detailed content of array_multisort() function in PHP: How to sort multiple arrays. For more information, please follow other related articles on the PHP Chinese website!