Summary of various methods of php array sorting_PHP tutorial
In PHP, it is very simple for us to sort one-dimensional arrays. We only need to use sort(), rsort() and it is done. If we want to sort multi-dimensional data, PHP does not have such a function, so we need it. Did it myself.
For php array sorting PHP provides a lot of functions. I will list them below. If not, you can add them.
The sort() function is used to sort array cells from low to high.
The rsort() function is used to sort array cells from high to low.
The asort() function is used to sort the array cells from low to high and maintain the index relationship.
The arsort() function is used to sort the array cells from high to low and maintain the index relationship.
The ksort() function is used to sort array cells from low to high by key name.
The krsort() function is used to sort array cells from high to low by key name.
But today we are mainly talking about the array sorting function that comes with PHP, mainly about custom sorting
1. Bubble sorting method
Description: Find the largest number, arrange it to the end, and then continue to find
Example:
The code is as follows | Copy code | ||||
$arr = array(3,5,- 1,0,2);
$temp = $arr[$j]; $arr[$j]=$arr[$j+1]; $arr[$j+1]=$temp; } } } |
Understanding:
3, 5, -1, 0, 2
//Start from the first number and compare backwards. If it is larger than the following number, adjust the position with the following number
//The first time, 3 is less than 5, then it remains unchanged
//The second time, 5 is greater than -1, then it becomes
3, -1, 5, 0, 2
//The third time, 5 is greater than 0
3, -1, 0, 5, 2
//The fourth time, 5 is greater than 2
3, -1, 0, 2, 5
This completes an inner loop. At this time, the last number is sorted and will not participate next time 3, -1, 0, 2, 5 The second outer loop begins. The first time: 3 is greater than -1
代码如下 | 复制代码 |
$arr=array(2,1,-1,3,0); for($i=0;$i $minindex = $i; for($j=1+$i;$j $minindex = $j; } } $temp = $arr[$i]; $arr[$i] = $arr[$minindex]; $arr[$minindex] = $temp; } |
The code is as follows | Copy code |
$arr=array(2,1,- 1,3,0);
for($i=0;$i |
Understanding:
2, 1, -1, 3, 0
//Assume that the first number 2 is the minimum value, and the subsequent numbers are compared with 2 in turn to find the smallest number
Process:
1 is less than 2, then minval=1
-1 is less than 1, then minval=-1
3 is greater than -1, unchanged
0 is greater than -1, unchanged
So now we have found the smallest number in the array, which is -1
Swap the positions of -1 and 2 to complete the sorting of the first number
So now the array becomes
-1, 1, 2, 3, 0
Now the first number -1 is already in order, so it will not participate in the comparison and continue to the next
Now assume minval=1
2 is greater than 1, unchanged
3 is greater than 1, unchanged
0 is less than 1, then minval=0
Now that one cycle is completed, swap the positions of 0 and 1 to complete the sorting of the second number
So now the array becomes
-1, 0, 2, 3, 1
//The following push method is the same as above. . .
3. Insertion sort method description: First assume that the first number in an array is a separate ordered array, and then compare the following number with it [as I grows here, it becomes them]. If If the following number is smaller than the assumed number, move the smaller number back, and finally move that number to the front
The code is as follows | Copy code | ||||
$arr=array(2,1,- 1,3,0);
|
Understanding:
2, 1, -1, 3, 0
//For the first time, save the number 1 to be inserted as insertval, and then compare insertval with 2. 1 is less than 2, so move 2 back to become the following picture
2, 2, -1, 3, 0
//At this time, there is no number in front of 2, insertindex=0, so the comparison is completed, then insert insertval to the found position. It becomes as shown below
1, 2, -1, 3, 0
//At this time, 1 and 2 become ordered arrays
//The second time, first save the number to be inserted -1 as insertval, and then compare insertval with 2. -1 is less than 2, so move 2 back to become the following picture
1, 2, 2, 3, 0
//At this time, compare insertval with 1. If -1 is less than 1, then move -1 back to become the following picture (this is a process of comparing the number to be inserted with the previous ordered array)
1, 1, 2, 3, 0
//At this point, insertindex has come to an end, so insert insertval at this position
-1, 1, 2, 3, 0
//The following method is as above
The two-dimensional array sorting function can achieve an ORDER BY effect similar to MySQL. It has special applications when the array is not obtained from the database.
The code is as follows | Copy code |
// Description: Sorting method of two-dimensional array in PHP |
www.bkjia.com
truehttp: //www.bkjia.com/PHPjc/631627.htmlTechArticle

PHP is a server-side scripting language used for dynamic web development and server-side applications. 1.PHP is an interpreted language that does not require compilation and is suitable for rapid development. 2. PHP code is embedded in HTML, making it easy to develop web pages. 3. PHP processes server-side logic, generates HTML output, and supports user interaction and data processing. 4. PHP can interact with the database, process form submission, and execute server-side tasks.

PHP has shaped the network over the past few decades and will continue to play an important role in web development. 1) PHP originated in 1994 and has become the first choice for developers due to its ease of use and seamless integration with MySQL. 2) Its core functions include generating dynamic content and integrating with the database, allowing the website to be updated in real time and displayed in personalized manner. 3) The wide application and ecosystem of PHP have driven its long-term impact, but it also faces version updates and security challenges. 4) Performance improvements in recent years, such as the release of PHP7, enable it to compete with modern languages. 5) In the future, PHP needs to deal with new challenges such as containerization and microservices, but its flexibility and active community make it adaptable.

The core benefits of PHP include ease of learning, strong web development support, rich libraries and frameworks, high performance and scalability, cross-platform compatibility, and cost-effectiveness. 1) Easy to learn and use, suitable for beginners; 2) Good integration with web servers and supports multiple databases; 3) Have powerful frameworks such as Laravel; 4) High performance can be achieved through optimization; 5) Support multiple operating systems; 6) Open source to reduce development costs.

PHP is not dead. 1) The PHP community actively solves performance and security issues, and PHP7.x improves performance. 2) PHP is suitable for modern web development and is widely used in large websites. 3) PHP is easy to learn and the server performs well, but the type system is not as strict as static languages. 4) PHP is still important in the fields of content management and e-commerce, and the ecosystem continues to evolve. 5) Optimize performance through OPcache and APC, and use OOP and design patterns to improve code quality.

PHP and Python have their own advantages and disadvantages, and the choice depends on the project requirements. 1) PHP is suitable for web development, easy to learn, rich community resources, but the syntax is not modern enough, and performance and security need to be paid attention to. 2) Python is suitable for data science and machine learning, with concise syntax and easy to learn, but there are bottlenecks in execution speed and memory management.

PHP is used to build dynamic websites, and its core functions include: 1. Generate dynamic content and generate web pages in real time by connecting with the database; 2. Process user interaction and form submissions, verify inputs and respond to operations; 3. Manage sessions and user authentication to provide a personalized experience; 4. Optimize performance and follow best practices to improve website efficiency and security.

PHP uses MySQLi and PDO extensions to interact in database operations and server-side logic processing, and processes server-side logic through functions such as session management. 1) Use MySQLi or PDO to connect to the database and execute SQL queries. 2) Handle HTTP requests and user status through session management and other functions. 3) Use transactions to ensure the atomicity of database operations. 4) Prevent SQL injection, use exception handling and closing connections for debugging. 5) Optimize performance through indexing and cache, write highly readable code and perform error handling.

Using preprocessing statements and PDO in PHP can effectively prevent SQL injection attacks. 1) Use PDO to connect to the database and set the error mode. 2) Create preprocessing statements through the prepare method and pass data using placeholders and execute methods. 3) Process query results and ensure the security and performance of the code.


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

Atom editor mac version download
The most popular open source editor

MinGW - Minimalist GNU for Windows
This project is in the process of being migrated to osdn.net/projects/mingw, you can continue to follow us there. MinGW: A native Windows port of the GNU Compiler Collection (GCC), freely distributable import libraries and header files for building native Windows applications; includes extensions to the MSVC runtime to support C99 functionality. All MinGW software can run on 64-bit Windows platforms.

EditPlus Chinese cracked version
Small size, syntax highlighting, does not support code prompt function

Dreamweaver Mac version
Visual web development tools

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