How to reverse php array
How to implement array reversal in php: 1. Use the "function reverse($arr){...}" method to achieve array reversal; 2. Use "function reverse_arr($arr){... }" method can be used to reverse the array.
#The operating environment of this article: Windows 7 system, PHP version 7.4, Dell G3 computer.
php implements array reversal
There is a function in php that can reverse an array, which is often used in work and is very convenient. Let’s implement this function by ourselves today.
$arr = [2,5,6,1,8,16,12]; function reverse($arr){ $left = 0; $right = count($arr) -1; $temp = []; while ($left <= $right){ $temp[$left] = $arr[$right]; $temp[$right] = $arr[$left]; $left++; $right--; } ksort($temp); return $temp; } 效果 Array ( [0] => 12 [1] => 16 [2] => 8 [4] => 6 [5] => 5 [6] => 2 )
However, this function can only handle one-dimensional arrays. While implementing one that can handle multiple dimensions.
$arr = [2,[6,3,9],1,[5,2,1,[10,8,7]],5,0]; function reverse_arr($arr){ $index = 0; $reverse_array = []; foreach ($arr as $sub_arr){ if(is_array($sub_arr)){ $sub_arr = reverse($sub_arr); $arr_ = reverse_arr($sub_arr); $reverse_array[$index] = $arr_; }else{ $reverse_array[$index] = $sub_arr; } $index++; } return $reverse_array; } print_r(reverse(reverse_arr($arr))); 输出结果
Array ( [0] => 0 [1] => 5 [2] => Array ( [0] => Array ( [0] => 7 [1] => 8 [2] => 10 ) [1] => 1 [2] => 2 [3] => 5 ) [3] => 1 [4] => Array ( [0] => 9 [1] => 3 [2] => 6 ) [5] => 2 )
The above are all numeric index arrays and cannot handle associative arrays. Next comes the one that can handle associative arrays
$arr = ['a'=>'aa','b'=>'bb','c'=>'cc','d'=>'dd','e'=>'ee']; function reverse($arr){ $temp = []; end($arr); while (($value = current($arr)) != null){ $temp[key($arr)] = $value; prev($arr); } return $temp; } print_r(reverse($arr)); 结果 Array ( [e] => ee [d] => dd [c] => cc [b] => bb [a] => aa )
Recommended learning: "PHP Video Tutorial 》
The above is the detailed content of How to reverse php array. For more information, please follow other related articles on the PHP Chinese website!

Hot AI Tools

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Undress AI Tool
Undress images for free

Clothoff.io
AI clothes remover

AI Hentai Generator
Generate AI Hentai for free.

Hot Article

Hot Tools

Notepad++7.3.1
Easy-to-use and free code editor

SublimeText3 Chinese version
Chinese version, very easy to use

Zend Studio 13.0.1
Powerful PHP integrated development environment

Dreamweaver CS6
Visual web development tools

SublimeText3 Mac version
God-level code editing software (SublimeText3)

Hot Topics

How to use PHP arrays to generate and display charts and statistical graphs. PHP is a widely used server-side scripting language with powerful data processing and graphic generation capabilities. In web development, we often need to display charts and statistical graphs of data. Through PHP arrays, we can easily implement these functions. This article will introduce how to use PHP arrays to generate and display charts and statistical graphs, and provide relevant code examples. Introducing the necessary library files and style sheets Before starting, we need to introduce some necessary library files into the PHP file

How to use PHP arrays to generate dynamic slideshows and picture displays. Slideshows and picture displays are common functions in web design and are often used in scenarios such as carousels and gallery displays. As a popular server-side scripting language, PHP has the ability to process data and generate dynamic HTML pages, and is very suitable for generating dynamic slideshows and picture displays. This article will introduce how to use PHP arrays to generate dynamic slideshows and picture displays, and give corresponding code examples. Prepare image data First, we need to prepare a set of image path data

How to use PHP arrays to implement user login and permission management functions When developing a website, user login and permission management are one of the very important functions. User login allows us to authenticate users and protect the security of the website. Permission management can control users' operating permissions on the website to ensure that users can only access the functions for which they are authorized. In this article, we will introduce how to use PHP arrays to implement user login and permission management functions. We'll use a simple example to demonstrate this process. First we need to create

There are several ways to determine an array in PHP: 1. Use the count() function, which is suitable for all types of arrays. However, it should be noted that if the parameter passed in is not an array, the count() function will return 0; 2. Use the sizeof() function, which is more used to maintain compatibility with other programming languages; 3. Custom functions, By using a loop to traverse the array, each time it is traversed, the counter is incremented by 1, and finally the length of the array is obtained. Custom functions can be modified and expanded according to actual needs, making them more flexible.

PHP array key-value pair is a data structure consisting of a key and a corresponding value. The key is the identifier of the array element, and the value is the data associated with the key. It allows us to store and access data using keys as identifiers. By using key-value pairs, we can more easily operate and manage elements in the array, making program development more flexible and efficient.

PHP array is a very common data structure that is often used during the development process. However, as the amount of data increases, array performance can become an issue. This article will explore some performance optimization techniques for PHP arrays and provide specific code examples. 1. Use appropriate data structures In PHP, in addition to ordinary arrays, there are some other data structures, such as SplFixedArray, SplDoublyLinkedList, etc., which may perform better than ordinary arrays in certain situations.

An effective way to implement array union in PHP: use the array_merge() function to merge multiple arrays, but not merge duplicate values. Combine array_unique() and array_merge() to merge arrays and keep duplicate values. Create a custom function to merge arrays based on specific requirements, such as merging sorted arrays.

The functions that PHP uses to determine if an array is empty are the "empty()" function and the "count()" function. 1. The "empty()" function is used to determine whether a variable is empty, including determining whether an array is empty. Its syntax is "empty($variable)"; 2. The "count()" function is used to count arrays. The number of elements, the syntax is "count($array)".
