Month: October 2009

There are many ways to improve the way you write your PHP code. And we can easily increase the efficiency of our code just by putting in some effort during development. However, there might be some unknown information that you might not aware in PHP that can help improve your code. In this article, i will try to provide you with some tips that can serve as micro optimization for your code and could also add on to the list of knowledge that you have in PHP. We will also look at many benchmarking of these tips where possible!

Loop

Every program will required certain amount of loop. And loop is considered as efficiency killer if you have many nested loop (means loop in a loop) as one loop will required to run 'n' times and if you have 1 nested loop, this means your program will have to run n² times. Well, i think you can do the math. But we are not talking about this. There is something more interesting about loop in PHP. There are many ways we can define a loop in PHP. But how do you know which one is the best way to loop your data? Apparently, using a for loop is better than foreach and while loop if the maximum loop is pre-calculated outside the for loop! What do i mean? Basically is this.

#Worst than foreach and while loop
for($i =0; $i < count($array);$i++){
echo 'This is bad, my friend';
}

#Better than foreach and while loop
$total = (int)count($array);
for($i =0; $i < $total;$i++){
echo 'This is great, my friend';
}

The above shows two different ways of writing a for loop. The first way includes the operation count into the loop while the second one pre-calculate the total number of loop outside it. The difference between these two is that the second doesn't run count operation n times while the first one did. You can find this VERY interesting benchmarking on loops on  PHP.

Single Vs Double Quotes

Since i mentioned that benchmarking page on loops, it also includes the benchmark for single(') and double(") quotes. Now, between these two what is the best one to use? It really doesn't makes much differences. But i preferred to use  single(') quote because i don't have to press shift? Just kidding (not). That's one of the reason why i use a single quote over the double one. But the other reason is that PHP will scan through double quote strings for any PHP variables (additional operation) and usually i don't mix my variables and strings into one. I usually use single quote instead. However, you might also have aware that if an empty string is declared using a single quote, it seems like there is a performance pitfall. You or I might want to take note of that. Basically, there is a dollar($) symbols in your string, try to avoid double quote unless its variable?

Pre increment vs Post increment

Well, increment a certain value also have a few ways to improve. We all know that there are many ways to increment integer values such as

$i++;
$++i
$i+=1;
$i = $i + 1;

Out of all these what way is the most efficient? In PHP, it seems like pre increment is better than the other ways of performing an increment. Its around 10% better than post increment? The reason? Some said that post increment made certain copy unlike pre increment. There isn't any benchmark done for PHP but i found one on C++ which should be quite the same. Well, without a proper benchmark on this, i can't really confirm this. Furthermore, it really doesn't makes a big differences towards normal programmers but may affect those who are working towards micro optimization.  Nonetheless, many people do suggest pre over post increment in term of optimization.

Absolute Path VS Relative Path

Absolute path which is also known as full path compare to a relative path which will be better for PHP? Surprisingly, it seems that absolute path is better. Compare to relative path which might just help to screw up your include and require operation in PHP, absolute path doesn't. Well, that's the reason why i use absolute path. But the real reason is that using absolute path eliminate the need for the server to resolve the path for you. Simply to say, do you know where the file is located when you just look at a relative path or is it faster if i just throw you the full path?

Echo Vs Print

Yes! I know, echo is better. But how much better? Interested to know? I am interested. So i went to dig a bit on the internet and found some useful information for benchmarking between these two! Its around 12%-20% faster using echo compare to print when there is no $ symbol in the printing string. And around 40-80% faster if there is an $ symbol used in a printing string! This really demonstrate the differences between the keyword $ symbol used in PHP.

Dot Vs Commas Concatenation

Between dot and commas which way do you use to concatenate between two strings/variables? I personally used dot to concatenate my stuff. Such as the one shown below

$a = '10 PHP programming ';
$b = 'Improvement Tips';
#10 PHP Programming Improvement Tips
echo $a.$b;

I usually do the above. Instead of this,

$a = '10 PHP programming ';
$b = 'Improvement Tips';
#10 PHP Programming Improvement Tips
echo $a,$b;

Well, between these two which is more efficient? If you did visit the link for benchmarking between echo and print, you might have aware on the exact same test, they also have performed test case for dot and commas. The result shows that dot is more preferable if there are no variables or $ symbol involved which is around 200% faster. On the other hand, commas will help to increase around 20%-35% efficiency when dealing with $ symbols.

str_replace vs preg_replace vs ereg_replace

Ok! We have 3 string search function in PHP. Out of these three functions, which do you think will run the fastest? Some of you might have know, str_replace will run faster. Reason? str_replace doesn't run any complex expression unlike preg_replace and ereg_replace. Well, maybe many of you might know that but it is not necessary always str_replace that runs fastest. If you have to call str_replace 5 times compare to preg_replace, which will run faster? (str_replace, of course) Wrong! preg_replace runs 86.99% faster than 5 str_replace function call! Basically, i also have such doubt and search for such benchmark. The benchmark really explains some doubts we have in these functions.

Find Timestamp

When you want to find out the time when your script starts running in order to get that timestamp to store it into your database. The first thing you do is to fire up your Google and search for some PHP function. Well, after PHP5 you do not have to do that. After PHP 5 you can easily retrieve the execution timestamp of your script by using

$_SERVER['REQUEST_TIME']

This could really save some time digging for something that already exist within your reach.

explode Vs preg_split

Well, when you want to split a string what do you use in PHP? I usually used explode because it support even PHP4.0 and that's also what i was taught by my ex-colleagues. The answer in term of efficiency is explode. Split supports regular express and this makes it quite the same comparison between str_replace and preg_replace, anything that have regular expression support will usually be a bit more slower than those that doesn't support it. It took around 20.563% faster using explode in PHP.

Other Benchmarks

I believe this list can go on forever with such great benchmarking site i found. It basically shows you most of the benchmarking between PHP functions or those articles that claim whatever stuff is better than the other in PHP but doesn't provide you with any real evidence on their article. In this article, hopefully i have provided you with the necessary information for you to perform some micro optimization and also other more of such optimization through the benchmarking site.

Summary

I believe many of you have see all these information floating around the internet. But the only differences i see is that they don't really provides you with the real interesting part of this article, that is the benchmark of each test. This article really help me a lot with all the figures and testing given by all these great benchmarking site. Hopefully it also gives you the same result.

P.S: Most of these benchmark sites are run on real-time.