There are two ways to correctly use PHP comments: // or # for single-line comments, and / .../ for multi-line comments. In PHP syntax, you need to pay attention to each statement ending with a semicolon, adding $ before the variable name, and case sensitivity, using dots (.), and maintaining good indentation to improve readability. The PHP tag specification is to start with <?php. It is recommended to omit the end tag?> in pure PHP files to avoid unnecessary blank issues. Mastering these basic but key details can help improve code quality and collaboration efficiency.
When writing PHP code, comments and syntax are the basic but very critical parts. Many people tend to ignore these details when they first learn, but it is a headache to maintain it later. In fact, as long as you develop good habits at the beginning, this part is not difficult to deal with.
How to use PHP comments correctly?
There are two main ways to write comments in PHP: single-line comments and multi-line comments.
-
Single-line comments are usually used with
//or#, which are suitable for writing next to the code to make some simple explanations, such as:
// Output welcome message echo "Hello, World!";
Multi-line comments are used for
/* ... */, which is suitable for explaining a function or temporarily blocking a certain piece of code, for example:/* This function is used to calculate the sum of two numbers. $a and $b are both integers and return their summing result*/ function add($a, $b) { return $a $b; }
Writing comments is not to deal with checks, but to facilitate yourself or others to understand the code logic. Especially when multiple people collaborate, clear annotations can save a lot of communication costs.
What should be paid attention to in the basic PHP syntax?
The syntax of PHP does not seem complicated, but some small details are prone to errors:
Each statement must end with a semicolon , otherwise an error will be reported, such as forgetting to add a semicolon:
echo "This is a line" // Error! Less than that;
The variable name should be preceded by the
$symbol and is case sensitive
$nameand$Nameare two different variablesString splicing uses dots (.) , not the correct way to write the plus sign:
echo "Your name is:" . $name;
Indentation does not affect execution, but affects reading
Although PHP does not force indentation format, good indentation helps to quickly understand the code structure
These rules seem simple, but novices often fail to run the program due to negligence.
How to write PHP tags to standardize?
PHP files usually start with <?php and end with ?> . However, many projects now recommend only writing the start tag and omitting the end tag to avoid outputting extra spaces or line breaks.
For example, it is better to write this way:
<?php echo "Hello";
Instead:
<?php echo "Hello"; ?>
Especially in pure PHP files, omitting ?> is a common practice that can reduce problems caused by unexpected blanks.
In addition, if you miss HTML and PHP, you still need to close the tags, otherwise the HTML content will not be output as normal text.
Basically that's it. If the annotations are written clearly and the syntax is accurate, the code will be easier to read and less errors. These things seem basic, but persistence is the key to efficiency.
The above is the detailed content of PHP Comments and Syntax. For more information, please follow other related articles on the PHP Chinese website!
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