Best practice when parsing - how to speed it up?

[pepsi_max2k]

Hey all, I have a question about parsing HTML pages. I have a script that grabs one, stores it as $result, then runs numerous preg_match_all commands on $result (without changing it).

 

First I run a preg_match to find whether there's any values worth further parsing (looks for a single line). Then I run one preg_match_all to find all negative occurances of a value, then another preg_match_all to find all positive results of one type, if non are found then again to find them of a different type, then again to find them of a third type if there's none of a second.

 

That's one preg_match and up to four preg_match_alls on the same page, much of which contains data that's irrelevant to the parsing.

 

So I'm just wondering whether I should run a preg_replace to strip half of the text in $result away, in the hope it'll speed up the latter preg_match_alls? Or is the result not gonna be worth it - maybe preg_replace will take up so much extra time, I may as well leave it as it is?

 

 

 

Oh and while I'm here - if statements. Is using lots really gonna cause any speed issues? I have a few things like this in my code:

 

 if ($type=="Game") {
        // Alter search url based on console.
    	if ($console=="Xbox") {
    		do something
    	} elseif ($console=="PS1") {
    		do something else
    	} elseif ($console=="PS2") {
    		do something else
    	} elseif ($console=="PS3") {
    		do something else
    	} elseif ($console=="GameCube") {
    		do something else
    	} elseif ($console=="Xbox 360") {
    		do something else
    	} elseif ($console=="Wii") { 
    	    do something else
        } elseif ($console=="Nintendo DS") { 
    	    do something else
        }
    } elseif ($type=="Accessory") {
    	if ($console=="PS1") {
    		do something else
    	} elseif ($console=="PS2") {
            do something else
        } else {
    		do something else
    	} 
} else {
       do something else
}

 

Seems a bit, erm... slow to read though. Just seems there'd be a quicker way...

[CarbonCopy]

http://www.developertutorials.com/tutorials/php/displaying-load-time-php-050620/page1.html

 

See what the load time is. It may not be the script that's slow

 

preg_replace shouldn't make any noticeable difference with such a small number of preg_match commands.

 

For the if statements, a switch statement may be faster with a large number of options. I'll go check

EDIT: Switch statements are twice as fast with integer conditions, but for strings, there is no noticable difference.

 

Remember, Google is our friend.