


Summary of the differences between the strstr, strrchr, substr, and stristr functions in PHP, strstrstristr_PHP tutorial
Summary of the differences between the strstr, strrchr, substr, and stristr functions in php, strstrstristr
The difference in usage of the four functions strstr, strrchr, substr, and stristr in php:
The four string operation functions strstr strrchr substr stristr in PHP are particularly confusing. The commonly used ones are substr and strstr, which can basically satisfy the operation of strings.
The following is an introduction to the differences between these functions.
1. The difference between strstr and strcchr
strstr displays the first string found, the string to be found, and subsequent strings.
strrchr displays the last string found, the string to be found, and the following strings.
$email = 'test@test.com@jb51.net';
$domain = strstr($email, '@');
echo "strstr test result $domain
";
$domain = strrchr($email, '@');
echo "strrchr test results $domain
";
?>
The results are as follows:
strstr test results @test.com@jb51.net
strrchr test results @jb51.net
2. The difference between strstr and strstr
strstr is case sensitive.
stristr is case-insensitive.
$email = 'zhangYing@jb51.net';
$domain = strstr($email, 'y');
echo "strstr test result $domain
";
$domain = stristr($email, 'y');
echo "stristr test results $domain
";
?>
The results are as follows:
strstr test results jb51.net
stristr test results Ying@jb51.net
3. The difference between strstr and substr
strsr is intercepted after matching.
substr does not match and is intercepted based on the starting position.
$email = 'zhangYing@jb51.net';
$domain = strstr($email, 'y');
echo "strstr test result $domain
";
$domain = substr($email,-7);
echo "substr test results $domain
";
?>
The results are as follows:
strstr test results jb51.net
substr test results jb51.net
After understanding these string interception functions, you can save a lot of trouble during development
$a = array();
$a[] = "Project";
$a[] = "Title";
$a[] = "Time";
return $a
In fact, there is no need to search everywhere for so-called "commonly used functions". The so-called "commonly used functions" vary from person to person. Someone often uses a certain function, but it does not mean that you will also use it frequently. There are many PHP functions. It is key to always have a PHP help manual. If you encounter something you are not familiar with, check it out. The more times you check it, the more often it will become "commonly used".
Generally speaking, string, array, and database class functions are relatively commonly used categories.
The functions are listed below for reference only.
=========================================
//================================Time and Date========= ======================
//y returns the last two digits of the year, the four-digit number of year Y, the number of month m, and the English month of M. d number of the month, D day of the week in English
$date=date("Y-m-d");
//include,include_once.require,require_once
//require("file.php" ) Before the PHP program is executed, the files specified by require will be read in. If an error occurs, it will be fatal.
//include("file.php") can be placed anywhere in the PHP program. The file specified by include will not be read until the PHP program is executed. If an error occurs,
//= ==============================Output printing================== =============
//sprintf("%d","3.2") ;//Only formatting, return the formatted string, no output.
//printf("%d","3.2") ;//Formatting and output
//print("3.2") ;//Only output
//echo "nihao" ,"aa";//Can output multiple strings
//print_r(array("a","b","c"));//Display the key values and elements of the array in sequence
//============================== Commonly used string functions========== =====================
//Get the length of the string, how many characters there are, spaces are also counted
$str=" sdaf sd ";
$len=strlen($str);
//Use the string in the first parameter to connect each element in the subsequent array and return a string.
$str=implode("-",array("a","b","c"));
//String splitting method, returns an array, using the first parameter The characters in will split the following string, and intercept the characters before, after, and between the specified characters. If the specified character is at the beginning or end, the element at the beginning or end of the returned array will be an empty string
//If it is not divided into a string, Returns a null value to the corresponding element of the array. The last limit returns the length of the array. If there is no limit, it will continue to be divided.
$array=explode("a","asdd...the rest of the text>>

To protect the application from session-related XSS attacks, the following measures are required: 1. Set the HttpOnly and Secure flags to protect the session cookies. 2. Export codes for all user inputs. 3. Implement content security policy (CSP) to limit script sources. Through these policies, session-related XSS attacks can be effectively protected and user data can be ensured.

Methods to optimize PHP session performance include: 1. Delay session start, 2. Use database to store sessions, 3. Compress session data, 4. Manage session life cycle, and 5. Implement session sharing. These strategies can significantly improve the efficiency of applications in high concurrency environments.

Thesession.gc_maxlifetimesettinginPHPdeterminesthelifespanofsessiondata,setinseconds.1)It'sconfiguredinphp.iniorviaini_set().2)Abalanceisneededtoavoidperformanceissuesandunexpectedlogouts.3)PHP'sgarbagecollectionisprobabilistic,influencedbygc_probabi

In PHP, you can use the session_name() function to configure the session name. The specific steps are as follows: 1. Use the session_name() function to set the session name, such as session_name("my_session"). 2. After setting the session name, call session_start() to start the session. Configuring session names can avoid session data conflicts between multiple applications and enhance security, but pay attention to the uniqueness, security, length and setting timing of session names.

The session ID should be regenerated regularly at login, before sensitive operations, and every 30 minutes. 1. Regenerate the session ID when logging in to prevent session fixed attacks. 2. Regenerate before sensitive operations to improve safety. 3. Regular regeneration reduces long-term utilization risks, but the user experience needs to be weighed.

Setting session cookie parameters in PHP can be achieved through the session_set_cookie_params() function. 1) Use this function to set parameters, such as expiration time, path, domain name, security flag, etc.; 2) Call session_start() to make the parameters take effect; 3) Dynamically adjust parameters according to needs, such as user login status; 4) Pay attention to setting secure and httponly flags to improve security.

The main purpose of using sessions in PHP is to maintain the status of the user between different pages. 1) The session is started through the session_start() function, creating a unique session ID and storing it in the user cookie. 2) Session data is saved on the server, allowing data to be passed between different requests, such as login status and shopping cart content.

How to share a session between subdomains? Implemented by setting session cookies for common domain names. 1. Set the domain of the session cookie to .example.com on the server side. 2. Choose the appropriate session storage method, such as memory, database or distributed cache. 3. Pass the session ID through cookies, and the server retrieves and updates the session data based on the ID.


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

Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Article

Hot Tools

SAP NetWeaver Server Adapter for Eclipse
Integrate Eclipse with SAP NetWeaver application server.

VSCode Windows 64-bit Download
A free and powerful IDE editor launched by Microsoft

SecLists
SecLists is the ultimate security tester's companion. It is a collection of various types of lists that are frequently used during security assessments, all in one place. SecLists helps make security testing more efficient and productive by conveniently providing all the lists a security tester might need. List types include usernames, passwords, URLs, fuzzing payloads, sensitive data patterns, web shells, and more. The tester can simply pull this repository onto a new test machine and he will have access to every type of list he needs.

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

Safe Exam Browser
Safe Exam Browser is a secure browser environment for taking online exams securely. This software turns any computer into a secure workstation. It controls access to any utility and prevents students from using unauthorized resources.