Summary of PHP code optimization skills (36 PHP optimization tips)

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 does not return a value, while 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() consumes more resources; 7. Use absolute paths in includes and requires so that it takes less time to analyze the path; 8. If you need to get the time from sexinsex to when the script is executed, $_SERVER['REQUSET_TIME'] is better than time(); 9. If you can use character processing functions, try to use them because they are more efficient than regular expressions;// 10. str_replace character replacement is faster than regular replacement preg_replace, but strtr is 1/4 faster than str_replace; 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 to replace only one character at a time instead of accepting arrays as Find and replace parameters. Big things are reduced to small things, 1+1>2; 12. Using @ to cover up errors will slow down the script; 13. $row['id'] is 7 times faster than $row[id]. It is recommended to develop the habit of adding quotes to array keys; 14. Error messages are useful; 15. Don’t use functions in loops. For example, For($x=0; $x prop++) is 3 times slower than local variables; 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 (the same as declaring the same number of local variables). PHP may check whether the global variable exists; 20. The performance of methods has nothing to do with the number of methods defined in a class, 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); 21. The performance of methods in subclasses is better than that in base classes; 22. A function that calls only one parameter and has an empty function body takes 7-8 $localvar++ operations to run, while a similar method (a function in a class) takes about 15 $localvar++ operations to run; 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 small number of scripts; 25. Unless you have caching installed, your php script will need 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 eliminating some repeated compilation; 26. It is recommended to use memcached, a high-performance distributed memory object caching system, to improve the performance of network applications and reduce the burden on the database; 27. 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, addresses can be easily 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 using the ternary operator (?:); 31. Before you think about completely redoing your project, see if PEAR has what you need. PEAR is a huge resource library that many PHP developers know; 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 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 on the first line of each script file (or use require_once() to load it). Effectively protect sensitive SQL queries and paths from being displayed when errors occur; 34. Use gzcompress() and gzuncompress() to compress (decompress) large-capacity strings when storing (retrieving) the database. This built-in function can compress up to 90% using the gzip algorithm; 35. Make a function 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; 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(); Articles you may be interested in: 40 Tips for Optimizing PHP Code