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Optimizing PHP is of a great importance, though it has not much impact in a small script, however the bigger the script is becoming some shortcomings can cause much inconvenience later. Here are several facts (although some of them could be disputed about) that may help you in choosing the the right way to achieve the best results.

1. echo is faster than print, despite of that both are constructors, print is returning boolean result, echo returns nothing.

2. printf is much more slower than echo or print, it must handle additional parameters

3. avoid as much as possible magic methods like __get, __set, __autoload

4. when searching string in another string strstr() is faster than preg functions, however if you want to know if that string exists use strpos().

5. ++$i works faster than $i++. This is PHP unique behavior.

6. echo ‘Hello world’ works faster than echo “Hello world”, although speed difference is very tiny.

7. $arr[‘id’] works much more faster than $arr[id]

8. if you need to print a bigger piece of text without PHP variables just exit PHP (?>) and enter it when you need it again (<?php).

9. ctype functions are faster than regular expressions. More info at http://php.net/ctype

10. errors suppression with ‘@’ is useful, but makes script load slower.

11. use full OS paths, /home/user/public_html/images/ instead of just images/

12. don’t use variables if they will be used just 1 time.

13. if you want to assign variable to one of the array indexes, don’t do $var=$arr[‘foo’], better choice would be use references. $var=&$arr[‘foo’], now you just creating a reference to $arr[‘foo’] instead of duplicating it’s value.

14. use $_SERVER[’REQUEST_TIME’] instead of every time calling time() function. For example declare constant at the config file: define(“TIME”, $_SERVER[’REQUEST_TIME’]) and use TIME when you want to know timestamp.

15. isset($arr[‘foo‘]) works faster than in_array(‘foo’, $arr)

16. require_once() is useful, but works slower than common require()

17. never use unwanted functions in loop header, for($i=0; $i<count($foo); $i++) - will count $foo on every loop step

18. don’t use database queries in loops. Every major database system has enough possibilities to handle out that situation

19. mysql_fetch_array() will return an array with both index types, mysql_fetch_assoc() will not return numerical indexed array, mysql_fetch_row() will return just numerical indexed array

20. You must avoid several writing in one file. Better choice is to collect all data and with one writing session update file.

To conclude, it not always possible to follow these ways of optimizing the PHP. The main point of optimizing is that if you include as much optimizing tips in your script, the shorter the execution time of it will be and vice verse – the longer the script with only minimal optimization tips will prolong its execution time.

This entry was posted on Thursday, November 1st, 2007 at 12:09 pm and is filed under Programming. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.