Comments should explain "why" rather than "what was done", such as explaining business reasons rather than repeating code operations; 2. Add overview comments before complex logic, briefly explaining the process steps to help establish an overall impression; 3. Comments the "strange" code to explain the intention of unconventional writing, and avoid misunderstandings as bugs; 4. Comments are recommended to be concise, use // in single lines, use // in functions/classes/*.../ in order to maintain a unified style; 5. Avoid issues such as out of synchronization with the comments, too long comments or not deletion of the code, and ensure that the comments truly improve the readability and maintenance of the code.

This article answers several key questions for beginners to learn PHP. First, the method to quickly get started with basic syntax is to practice basic structures such as variables, conditional judgment and loops, such as using $ to define variables, echo output content, and if judgment conditions; second, the way to use PHP and HTML is to embed PHP code into HTML, wrap it, and pay attention to running in a server environment that supports PHP; third, the process of handling form submission and database connection includes: front-end submission of forms, PHP receives data, verifying data, using mysqli or PDO and other methods to connect to the database and perform insertion operations. At the same time, it is recommended to use ORM tools to improve security and convenience. The article emphasizes that learning PHP should focus on hands-on practice and gradually accumulate experience.

PHP string splicing uses dot operators, such as $a="Hello".$"World"; variables can be directly embedded in double quotes, such as echo "Hello,$name"; when splicing a large amount of content, it is recommended to initialize the empty string and append it, or use the array implode() to optimize performance; common errors include single quotes without parsing variables, missing punctuation marks, variables not assigned, etc. Note: 1. Dot numbers are used to concatenate any string 2. Double quotes support variable replacement but do not parse complex expressions 3. It is recommended to initialize first and then add gradually 4. Avoid mixing quotes causing variables to be unparsed.

When using if/else control structure for conditional judgment in PHP, the following points should be followed: 1. Use if/else when different code blocks need to be executed according to the conditions; 2. Execute if branches if the condition is true, enter else or elseif if they are false; 3. When multi-conditional judgment, elseif should be arranged in logical order, and the range should be placed in front of the front; 4. Avoid too deep nesting, it is recommended to consider switch or reconstruction above three layers; 5. Always use curly braces {} to improve readability; 6. Pay attention to Boolean conversion issues to prevent type misjudgment; 7. Use ternary operators to simplify the code in simple conditions; 8. Merge and repeat judgments to reduce redundancy; 9. Test boundary values to ensure the complete logic. Mastering these techniques can help improve code quality and stability.

Good comments can improve the readability of PHP code, the key is to explain "why" rather than "what to do". 1. Comments should explain the code intention, such as explaining the logic rather than repeating the code; 2. Add a brief description before complex logic to help quickly understand the purpose of the function; 3. Use comments to remind people of easy errors or special requirements, such as format or logic precautions; 4. Use TODO and FIXME to mark up to do or repair work to facilitate subsequent follow-up; 5. Keep comments and code updated synchronously to avoid misleading. Comments should be accurate, necessary and consistent in order to truly improve the readability of the code.

The first step is to clarify the goal, install the environment, write basic code, and learn to debug. First, determine what to do with PHP, then install the running environment with integrated tools, recommend XAMPP, Laragon or MAMP, and then write a simple PHP page to practice. Finally, master debugging methods such as opening error prompts, printing variables, and viewing logs, and gradually improve without rushing to achieve success.

There are two main ways to install PHP on Linux: use package manager to install and source code to compile and install. For newbies or users who do not have special requirements for the version, it is recommended to use a package manager to install it. For example, running sudoaptupdate and sudoaptinstallphp on Ubuntu/Debian. On CentOS, you can first install the EPEL source and then install it with yum. After the installation is completed, you can verify through php-v and install common extensions. If you need a specific version or custom function, you should choose source code compilation and installation. The specific steps include downloading the source code package, decompression, and configuration (such as ./configure--prefix=/usr/local/php--with-co

To quickly build a PHP environment, you can choose integrated tools such as XAMPP or MAMP, 1. Determine the environment selection: XAMPP and MAMP are suitable for beginners; 2. Install PHP: Download and decompress, configure environment variables and php.ini; 3. Use a web server: Apache is easier to use, and Nginx is suitable for high concurrency; 4. Debugging problems: Turn on error reports, check logs to check blank pages, database connection failures, or extension loading exceptions.