


Example code for PHP strstr function to determine whether a string exists_PHP tutorial
PHP strstr Definition and Usage
strstr() function searches for the first occurrence of a string in another string.
This function returns the rest of the string (from the matching point). Returns false if the searched string is not found.
Syntax
strstr(string,search)
参数 | 描述 |
---|---|
string | 必需。规定被搜索的字符串。 |
search | 必需。规定所搜索的字符串。如果该参数是数字,则搜索匹配数字 ASCII 值的字符。 |
Tips and Notes
Note: This function is binary safe.
Note: This function is case sensitive. For case-insensitive searches, use stristr().
Example
Example 1
echo strstr("Hello world!","world ");
?>
Output:
world!
Example 2
In this example, we will search for the character represented by the ASCII value of "o":
echo strstr("Hello world!",111) ;
?>
Output:
o world!
PHP uses strstr() function to prevent spam comments
If your website has a lot of spam comments, most of the spam comments have links. Because you want to increase backlinks, you can use the following tips to eliminate spam comments with links.
$content = $_POST['content '];
$garbage = strstr($content, "if($garbage == false)
{
// Database insertion code
}
else
{
echo "<script>alert('Your comment cannot contain links'); history.go(-1);</script>";
}
?>
PHP uses REFERER root access to jump to the address
For example, I developed a Yellow Pages source code and uploaded it to Webmaster's home. I previously set a demo program address: http://www.jb51.net. But now this domain name needs to be used for other sites, and what should I do if the original demo address becomes invalid? Then I can use PHP REFERER to determine the source. If it comes from the address of the webmaster's download station, I will transfer it to the site domain name.
I placed the following code in index.php on the site http://www.jb51.net to allow access from files.jb51.net to locate my server’s commonly used software downloads http://s.jb51.net
You can go to the demo address on this page
$referHost = parse_url($_SERVER['HTTP_REFERER'], PHP_URL_HOST);
$validDomain = 'files.jb51.net';
$ valid = strstr($referHost, $validDomain) == $validDomain;
if(!empty($valid)){
echo '<script>location.href="http://s.jb51. net";</script>';
exit;
}

What’s still popular is the ease of use, flexibility and a strong ecosystem. 1) Ease of use and simple syntax make it the first choice for beginners. 2) Closely integrated with web development, excellent interaction with HTTP requests and database. 3) The huge ecosystem provides a wealth of tools and libraries. 4) Active community and open source nature adapts them to new needs and technology trends.

PHP and Python are both high-level programming languages that are widely used in web development, data processing and automation tasks. 1.PHP is often used to build dynamic websites and content management systems, while Python is often used to build web frameworks and data science. 2.PHP uses echo to output content, Python uses print. 3. Both support object-oriented programming, but the syntax and keywords are different. 4. PHP supports weak type conversion, while Python is more stringent. 5. PHP performance optimization includes using OPcache and asynchronous programming, while Python uses cProfile and asynchronous programming.

PHP is mainly procedural programming, but also supports object-oriented programming (OOP); Python supports a variety of paradigms, including OOP, functional and procedural programming. PHP is suitable for web development, and Python is suitable for a variety of applications such as data analysis and machine learning.

PHP originated in 1994 and was developed by RasmusLerdorf. It was originally used to track website visitors and gradually evolved into a server-side scripting language and was widely used in web development. Python was developed by Guidovan Rossum in the late 1980s and was first released in 1991. It emphasizes code readability and simplicity, and is suitable for scientific computing, data analysis and other fields.

PHP is suitable for web development and rapid prototyping, and Python is suitable for data science and machine learning. 1.PHP is used for dynamic web development, with simple syntax and suitable for rapid development. 2. Python has concise syntax, is suitable for multiple fields, and has a strong library ecosystem.

PHP remains important in the modernization process because it supports a large number of websites and applications and adapts to development needs through frameworks. 1.PHP7 improves performance and introduces new features. 2. Modern frameworks such as Laravel, Symfony and CodeIgniter simplify development and improve code quality. 3. Performance optimization and best practices further improve application efficiency.

PHPhassignificantlyimpactedwebdevelopmentandextendsbeyondit.1)ItpowersmajorplatformslikeWordPressandexcelsindatabaseinteractions.2)PHP'sadaptabilityallowsittoscaleforlargeapplicationsusingframeworkslikeLaravel.3)Beyondweb,PHPisusedincommand-linescrip

PHP type prompts to improve code quality and readability. 1) Scalar type tips: Since PHP7.0, basic data types are allowed to be specified in function parameters, such as int, float, etc. 2) Return type prompt: Ensure the consistency of the function return value type. 3) Union type prompt: Since PHP8.0, multiple types are allowed to be specified in function parameters or return values. 4) Nullable type prompt: Allows to include null values and handle functions that may return null values.


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