Understanding PHP Comments
PHP comments are parts of the code that are used to interpret logic, tag tasks, or temporarily block code and are not executed by the server. Its core functions include: 1. Improve the readability of the code, which facilitates quick understanding of others and future self; 2. Supports two formats: single-line comments (// or #) and multi-line comments (//); 3. Common uses cover function descriptions, complex logic explanations, TODO markings and disable code during debugging; 4. Effective comments should avoid duplicate code, explain the reasons rather than operations, keep it concise and add version records where necessary, thereby significantly improving code maintenance efficiency.
PHP comments are a very basic but extremely important part of writing code. When many people first learn programming, they may ignore the importance of comments and think that as long as the code can run. In fact, good comments not only make it easier for others to understand your code, but also save a lot of time when you look back at what you write.

What are PHP comments?
PHP comments are explanatory texts added in the code and will not be executed by the server. Their purpose is to interpret the code logic, mark to-do items, or temporarily block a piece of code.
PHP supports two common annotation styles:

- Single line comment: Use
//
or#
- Multi-line comments: Use
/* */
For example:
// This is a single line comment echo "Hello World"; /* This is a multi-line comment*/
You can add comments above the function to explain the purpose, or you can add a brief explanation next to the complex logic, so that others can read it smoother and you can look back on it more worry-free.

Why write comments?
Many people always think that "I remember it very clearly now and there is no need for comments", but the reality is: in a few days you may forget why you wrote it like this .
There are several practical benefits to writing comments:
- Help teamwork: When others take over your code, you can understand what you are doing faster.
- Remind yourself: For example, mark
// TODO: 需要优化这里性能
- Convenient during debugging: If you want to test whether a certain piece of code affects the function, you can comment it out directly without deleting it.
Sometimes a simple comment can avoid a "code guessing" game.
How to write valid comments?
When writing comments, it is not enough to just write something casually. The key is to be clear and useful. The following suggestions can be referred to:
Don't repeat the meaning of the code itself
For example, if you write// 设置变量为1
and then$a = 1;
this is equivalent to not writing.Explain "why" rather than "what did"
For example:// Use cache to reduce the number of database requests $data = get_cached_data();
Keep it simple and clear
Comments are not about writing essays, it is enough to explain the logic clearly in a few words.Add instructions before function/class
You can briefly describe the functions, parameters and return value types of this function.- Function or class starts to explain the purpose
- Complex condition judgment side explanation
- Mark unfinished tasks (such as
// TODO: 添加权限验证
) - Temporarily comment out the code block during debugging
- Version update history (optional)
Common usage scenarios for comments
Here are some places where you can often use comments:
Although these little habits seem inconspicuous, they will greatly improve the maintainability of the code in the long run.
Basically that's it. Although the comments are just a few lines of description, it is really helpful for the readability of the code and subsequent maintenance. Write it clearly, and the person who thanks you in the future will be yourself.
The above is the detailed content of Understanding PHP Comments. For more information, please follow other related articles on the PHP Chinese website!

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