Good writing standards improve PHP code execution efficiency [Part 1]

Use single quotes instead of double quotes to enclose strings, it will be faster. Because PHP will search for variables in strings surrounded by double quotes, single quotes will not. Note: only echo can do this, it is a "function" that can take multiple strings as parameters (Annotation: PHP Manual It is said that echo is a language structure, not a real function, so the function is enclosed in double quotes).

1. If you can define a class method as static, try to define it as static, and its speed will increase by nearly 4 times.

2. $row['id'] is 7 times faster than $row[id].

3. Echo is faster than print, and uses multiple parameters of echo (annotation: refers to using commas instead of periods) instead of string concatenation, such as: echo $str1, $str2.

4. Determine the maximum number of loops before executing the for loop. Do not calculate the maximum value every loop. It is best to use foreach instead.

5. Unregister unused variables, especially large arrays, to free up memory.

6. Try to avoid using __get, __set, __autoload.

7. require_once() is expensive.

8. Try to use absolute paths when including files, because it avoids the speed of PHP searching for files in include_path, and the time required to parse the operating system path will be less.

9. If you want to know the time when the script starts executing (annotation: the server receives the client request), it is better to use $_SERVER['REQUEST_TIME'] than time().

10. Functions replace regular expressions to complete the same function.

11. The str_replace function is faster than the preg_replace function, but the strtr function is four times more efficient than the str_replace function.

12. If a string replacement function can accept arrays or characters as parameters, and the parameter length is not too long, then you can consider writing an additional replacement code so that each parameter passed is a character instead of just writing one line of code. Accepts arrays as parameters for query and replace.

13. It is better to use a selective branch statement (translation annotation: switch case) than to use multiple if, else if statements.

14. Using @ to block error messages is very inefficient, extremely inefficient.

15. Turn on the mod_deflate module of apache to improve the browsing speed of web pages.

16. The database connection should be closed when finished using it, and do not use long connections.

17. Error messages are expensive.

18. Increasing local variables in methods is the fastest. Almost as fast as calling local variables in a function.

19. Incrementing a global variable is 2 times slower than incrementing a local variable.

20. Incrementing an object property (such as: $this->prop++) is 3 times slower than incrementing a local variable.

21. Incrementing an undefined local variable is 9 to 10 times slower than incrementing a predefined local variable.

22. Just defining a local variable without calling it in a function will also slow down the speed (to the same extent as incrementing a local variable). PHP will probably check to see if the global variable exists.

23. Method calls appear to be independent of the number of methods defined in the class, as I added 10 methods (both before and after the test method) and there was no change in performance.

24. Methods in derived classes run faster than the same methods defined in base classes.

25. Calling an empty function with one parameter takes the same time as performing 7 to 8 local variable increment operations. A similar method call takes close to 15 local variable increments.

26. The time for Apache to parse a PHP script is 2 to 10 times slower than parsing a static HTML page. Use more static HTML pages and less scripts.

27. Unless the script can be cached, it will be recompiled every time it is called. Introducing a PHP caching mechanism can often improve performance by 25% to 100% without compilation overhead.

Get LAMP Brothers’ original PHP tutorial CD/"Essential PHP in Details" for free. For details, please contact the official website customer service: http://www.lampbrother.net

PHPCMSSecondary development http:/ /yun.itxdl.cn/online/phpcms/index.php?u=5

WeChat development                                                                                                                                                       .cn/online/server/index.php?u=5

JavascriptCourse

http://yun.itxdl.cn/online/js/index.php?u=5

CTOTraining Camp