Optimize php code tips

Tips for optimizing PHP code
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, and print returns an integer type;
3. Set the maximum number of loops before the loop, not during the loop;
4. Destroy variables to free up memory, especially large arrays;
5. Avoid using magic like __get, __set, __autoload, etc. Method;
6. requiere_once() is more resource-intensive;
7. Use absolute paths in includes and requires, which will take less time to analyze the path;
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 expressions;//
10. str_replace character replacement is faster than regular replacement preg_replace, but strtr is faster than str_replace 1/4 faster;
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 and only replace one at a time. characters instead of accepting arrays
as search and replace parameters. Make big things small, 1+1>2;
12. Using @ to cover up errors will reduce the running speed of the script;
13. $row['id'] is 7 times faster than $row[id]. It is recommended to develop an array key plus The habit of quotation marks;
14. Error messages are very useful;
15. Don’t use functions inside loops, for example, For($x=0; $x < count($array); $x), count() function is outside Calculate first;
16. Creating a global variable is 2 times slower than a local variable;
17. Creating an object property (variable in a class) such as ($this- >prop++) is 3 times slower than a local variable;
18. Creating an undeclared local variable is 9-10 times slower than an initialized local variable;
19. Declaring a global variable that has not been used by any function will also reduce performance (as in declaring the same number of local variables)
The same amount), PHP may check whether this global variable exists;
20. The performance of the method has nothing to do with the number of methods defined in a class, because I added 10 or more methods
to the tested class ( There is no difference in the performance of these methods before and after the test method;
21. The performance of the method in the subclass is better than that in the base class;
22. The time it takes to run a function that calls only one parameter and has an empty function body is equal to 7 -8 $localvar++ operations, while
a similar method (function in the class) runs equal to about 15 $localvar++ operations;
23. 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; 24. In the apache server, it takes at least 2-10 times longer to generate a php script page than the corresponding HTML static page. , it is recommended to use more static HTML pages and a few scripts;
25. 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;
26. It is recommended to use memcached, a high-performance distributed memory object caching system, to improve dynamic network applications. Performance,
Reduce the burden on the database;
27. Use the ip2long() and long2ip() functions to convert the IP address into an integer and store it in the database instead of a character. This reduces storage space by almost 1/4. At the same time, addresses can be sorted and searched quickly;
28. 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;
29. If you are using php5 and mysql4.1 or above, consider using the improved function mysqli_* of mysql_*;
30. Try to use the ternary operator (?:);
31. When you want to completely redo your Before starting a project, see if PEAR has what you need. PEAR is a huge resource library,
many PHP developers know it;
32. Use highlight_file() to automatically print a well-formatted copy of the page source code;
33. Use the error_reporting(0) function to prevent potential Sensitive information is 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 use
require_once() to load it) This can effectively protect sensitive SQL queries and paths from being displayed when errors occur;
34. Use gzcompress() and gzuncompress() to compress (decompress) large-capacity strings before storing (retrieving) data from the database
hour. This built-in function can be compressed up to 90% using the gzip algorithm;
35. A function can have multiple return values ​​by referencing parameter variable addresses. You can add an "&" before the variable to indicate
pass by address rather than by value;
36. 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();