本文实例讲述了PHP函数nl2br()与自定义函数nl2p()换行用法。分享给大家供大家参考,具体如下:
使用情景
很多场合我们只是简单用textarea获取用户的长篇输入,而没有用编辑器。用户输入的换行以“\n”的方式入库,输出的时候有时候会没有换行,一大片文字直接出来了。这个时候可以根据库里的“\n”给文字换行。PHP有自带的函数nl2br(),我们也可以自定义函数nl2p()。
先来看看nl2br() 函数吧。
定义和用法
nl2br() 函数在字符串中的每个新行 (\n) 之前插入 HTML 换行符 (
)。
一个简单的例子:
<?php $str = "Welcome to www.bitsCN.com"; echo nl2br($str); ?>
运行结果的HTML代码:
Welcome to <br /> www.bitsCN.com
nl2p
nl2br 有个缺点,比如要用CSS做到段落缩进就比较麻烦,这个时候就需要 nl2p 了。将br换行换成段落p换行,比较简单是直接替换:
<?php function nl2p($text) { return "<p>" . str_replace("\n", "</p><p>", $text) . "</p>"; } ?>
比较详细的函数,可以试下:
/** * Returns string with newline formatting converted into HTML paragraphs. * * @param string $string String to be formatted. * @param boolean $line_breaks When true, single-line line-breaks will be converted to HTML break tags. * @param boolean $xml When true, an XML self-closing tag will be applied to break tags (<br />). * @return string */ function nl2p($string, $line_breaks = true, $xml = true) { // Remove existing HTML formatting to avoid double-wrapping things $string = str_replace(array('<p>', '</p>', '<br>', '<br />'), '', $string); // It is conceivable that people might still want single line-breaks // without breaking into a new paragraph. if ($line_breaks == true) return '<p>'.preg_replace(array("/([\n]{2,})/i", "/([^>])\n([^<])/i"), array("</p>\n<p>", '<br'.($xml == true ? ' /' : '').'>'), trim($string)).'</p>'; else return '<p>'.preg_replace("/([\n]{1,})/i", "</p>\n<p>", trim($string)).'</p>'; }
更多关于PHP相关内容感兴趣的读者可查看本站专题:《PHP运算与运算符用法总结》、《PHP网络编程技巧总结》、《PHP基本语法入门教程》、《php操作office文档技巧总结(包括word,excel,access,ppt)》、《php日期与时间用法总结》、《php面向对象程序设计入门教程》、《php字符串(string)用法总结》、《php+mysql数据库操作入门教程》及《php常见数据库操作技巧汇总》
希望本文所述对大家PHP程序设计有所帮助。

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.


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