38 Tips to Optimize PHP Code (Summary)

1. If a method can be static, declare it as static, and the speed can be increased by 1/4;

2. Echo is more efficient than print , because echo has no return value, print returns an integer;

3. Set the maximum number of loops before the loop, not during the loop;

4. Destroy variables to release memory , especially large arrays;

5. Avoid using magic methods like __get, __set, __autoload, etc.;

6. requirere_once() is more resource intensive;

7 , Use absolute paths in includes and requires, so you spend less time analyzing paths;

8. If you need to get the time from sexinsex to script execution, $_SERVER['REQUSET_TIME'] is better than time ();

9. If you can use character processing functions, try to use them, because the efficiency is higher than regular;

10. str_replace character replacement is faster than regular replacement preg_replace, but strtr is faster than str_replace. Fast 1/4;

11. If a function can accept both arrays and simple characters as parameters, such as character replacement, and the parameter list is not too long, you can consider using more concise replacement statements, once Replaces only one character instead of accepting arrays as search and replace arguments. Make big things small, 1 1>2;

12. Covering errors with @ will reduce the running speed of the script;

13.$row['id'] is faster than $row[id] 7 times, it is recommended to develop the habit of adding quotation marks to array keys;

14. Error messages are very useful;

15. Do not use functions in loops, such as For($x=0; $ x < count($array); $x), the count() function calculates first outside;

16. Creating local variables in a method is the fastest, 97xxoo is almost the same as calling local variables in a method Fast;

17. Creating a global variable is 2 times slower than local variables;

18. Creating an object property (variable in a class) such as ($this->prop) 3 times slower than local variables;

19. Creating an undeclared local variable is 9-10 times slower than an initialized local variable;

20. Declaring an undeclared local variable is 9-10 times slower than an initialized local variable. Global variables used by functions will also reduce performance (the same as declaring the same number of local variables). PHP may check whether the global variable exists;

21. The performance of methods is different from that defined in a class The number of methods does not matter, because there is no performance difference after I add 10 or more methods to the tested class (these methods are before and after the test method);

22. The performance of methods in subclasses is excellent Because in the base class;

23, a function that only calls one parameter and has an empty function body takes 7-8 $localvar operations to run, while a similar method (function in the class) runs Equivalent to about 15 $localvar operations;

24. Surrounding your string by ' instead of ” will make things interpret a little faster since php looks for variables inside “…” but not inside ‘…’. Of course you can only do this when you don't need to have variables in the string.

25. It is faster to use commas instead of dots when outputting strings. Note: This only works for echo. This function Can accept some strings as parameters;

26. In the apache server, a PHP script page takes at least 2-10 times more time to generate than the corresponding HTML static page. It is recommended to use more static HTML pages and a small amount of Steps;

27. Unless you have a cache installed, your php script needs to be recompiled every time it is accessed. It is recommended to install a PHP caching program, which can significantly improve your performance by 20-100% by removing some repeated compilation;

28. It is recommended to use memcached, a high-performance distributed memory object caching system, to improve Dynamic network application performance, reducing the burden on the database;

29. Use the ip2long() and long2ip() functions to convert the IP address into an integer type and store it in the database instead of a character type. This reduces storage space by almost 1/4. At the same time, it is easy to sort and quickly search addresses;

30. Use checkdnsrr() to confirm the validity of some email addresses through the existence of domain names. This built-in function can ensure that each domain name corresponds to an IP address. ;

31. Try to like using the ternary operator (?:);

32. Before you want to completely redo your project, see if PEAR has what you need . PEAR is a huge resource library, as many PHP developers know;

33. Use highlight_file() to automatically print a well-formatted copy of the page source code;

34. Use the error_reporting(0) function to prevent potentially sensitive information from being displayed to the user. Ideally error reporting should be completely disabled in the php.ini file. But if you are using a shared virtual host and you cannot modify php.ini, then you'd better add the error_reporting(0) function and put it on the first line of each script file (or load it with require_once()). This can Effectively protect sensitive SQL queries and paths from being displayed when errors occur;

35. Use gzcompress() and gzuncompress() to compress (decompress) large-capacity strings before storing (retrieving) them from the database hour. This built-in function can be compressed to 90% using the gzip algorithm;

36. A function can have multiple return values ​​by referencing the parameter variable address. You can add an "&" before the variable to indicate passing it by address rather than by value;

37. Fully understand “magic quotes” and the dangers of SQL injection. I'm hoping that most developers reading this are already familiar with SQL injection. However, I list it here because it's absolutely critical to understand. If you' ve never heard the term before, spend the entire rest of the day googling and reading.

38. Using strlen() is not very fast because it needs to call some other operations such as lowercase and hash table queries. We can Use isset() to achieve similar functions. isset() is faster than strlen();

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