search
HomeBackend DevelopmentPHP Tutorialreplace function Summary of the use of str_replace function in PHP

During this time, I was reading the book "PHP and MySQL Web Development" and saw the explanation of str_replace. A small tip was written: You can use arrays to pass in all three of str_replace, but the explanation is relatively simple, so I decided to test this function myself. The execution result when each parameter is passed into the array.
Function prototype: mixed str_replace(mixed needle, mixed new_needle, mixed haystack[,int &count]);
needle: the string to be replaced, new_needle: the string used for replacement, haystack: the operation string, count: the number of replacements [Optional parameters]
We focus on testing the first three execution methods when using arrays:
When no array is used, this function directly uses new_needle to replace all needles and returns the replaced string. For example: str_replace("m","n","my name is jim!") returns ny nane is jin!
1. Only use arrays for needles.
Example: str_replace(array('m','i'),'n',"my name is jim!"); Return: ny nane ns jnn!
It can be seen that the function sequentially pairs each element in the array Replace the string and return the replaced string.
2. Only use arrays for new_needle.
Example: str_replace('m',array('n','z'),"my name is jim!n") returns: Arrayy naArraye is jiArray!
This replacement is more interesting, if it is used only for the second parameter Array, the function uses it as a string Array, replacing all needles with arrays.
3. Only use arrays for haystack.
Example: str_replace("m","n",array("my name is jim!","the game is over!")) The execution result of this statement returns an array, which is the two strings passed in. The result after replacement.
If you output the array content, you will see: ny nane is jin! the gane is over!
4. Use arrays for both needle and new_needle.
Example: str_replace(array("m","i"),array("n","z"),"my name is jim!") returns: ny nane zs jzn!
View the execution results and you can see that if If the first two parameters use arrays, the function replaces the strings of each object item in the array, and replaces the first item of needle with the first item of new_needle. And so on.
If the needle array is longer than new_deedle, for example: str_replace(array("m","i","s"),array("n","z"),"my name is jim!"); return: ny nane z jzn! It can be seen that the extra strings in the needle array are replaced with empty strings.
If the new_needle array is longer than needle, for example: str_replace(array("m","i"),array("n","z","x"),"my name is jim!") returns ny nane zs jzn! It can be seen that the redundant items of new_needle are ignored.
5. All three parameters use arrays.
For example: array content returned by str_replace(array("m","i"),array("n","z"),array("my name is jim!","the game is over")): ny nane zs jzn!the gane zs over
This is easier to understand. Replace the two strings separately.
A brief summary to prevent yourself from forgetting!

The above has introduced the replace function. A summary of the use of str_replace function in PHP, including the content of the replace function. I hope it will be helpful to friends who are interested in PHP tutorials.

Statement
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn
How can you protect against Cross-Site Scripting (XSS) attacks related to sessions?How can you protect against Cross-Site Scripting (XSS) attacks related to sessions?Apr 23, 2025 am 12:16 AM

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.

How can you optimize PHP session performance?How can you optimize PHP session performance?Apr 23, 2025 am 12:13 AM

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.

What is the session.gc_maxlifetime configuration setting?What is the session.gc_maxlifetime configuration setting?Apr 23, 2025 am 12:10 AM

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

How do you configure the session name in PHP?How do you configure the session name in PHP?Apr 23, 2025 am 12:08 AM

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.

How often should you regenerate session IDs?How often should you regenerate session IDs?Apr 23, 2025 am 12:03 AM

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.

How do you set the session cookie parameters in PHP?How do you set the session cookie parameters in PHP?Apr 22, 2025 pm 05:33 PM

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.

What is the main purpose of using sessions in PHP?What is the main purpose of using sessions in PHP?Apr 22, 2025 pm 05:25 PM

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 can you share sessions across subdomains?How can you share sessions across subdomains?Apr 22, 2025 pm 05:21 PM

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.

See all articles

Hot AI Tools

Undresser.AI Undress

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

AI Clothes Remover

Online AI tool for removing clothes from photos.

Undress AI Tool

Undress AI Tool

Undress images for free

Clothoff.io

Clothoff.io

AI clothes remover

Video Face Swap

Video Face Swap

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

Hot Tools

mPDF

mPDF

mPDF is a PHP library that can generate PDF files from UTF-8 encoded HTML. The original author, Ian Back, wrote mPDF to output PDF files "on the fly" from his website and handle different languages. It is slower than original scripts like HTML2FPDF and produces larger files when using Unicode fonts, but supports CSS styles etc. and has a lot of enhancements. Supports almost all languages, including RTL (Arabic and Hebrew) and CJK (Chinese, Japanese and Korean). Supports nested block-level elements (such as P, DIV),

SublimeText3 English version

SublimeText3 English version

Recommended: Win version, supports code prompts!

WebStorm Mac version

WebStorm Mac version

Useful JavaScript development tools

SublimeText3 Mac version

SublimeText3 Mac version

God-level code editing software (SublimeText3)

SublimeText3 Linux new version

SublimeText3 Linux new version

SublimeText3 Linux latest version