20 elements to improve PHP programming efficiency

【Summary】Use single quotes instead of double quotes to enclose strings, it will be faster. Because PHP will search for variables in the string surrounded by double quotes, single quotes will not. You can do this, it is a "function" that can take multiple strings as parameters 　 1. If you can define a class method as static, try to define it as static, and its speed will increase Nearly 4 times. 2. The speed of $row[’id’] is 7 times that of $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 those 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 accepts 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: switch case) than to use multiple if, else if statements.

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

　15. Opening the mod_deflate module of apache can 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.