This post is part 2 of a 3 part series. For the other parts, visit these posts:
Tips for faster PHP scripts
Even More Tips for faster PHP scripts
Here's the list:
6. Pre-increment is faster than post-increment
Try to pre-increment, rather than post-increment, where possible. It is faster because post-increment creates a temporary variable while in the process of incrementing. So, this:
++$var;
…is faster than this:
$var++;
This rule also applies to decrementation as well. To test this assertion, I created two for loops. The first for loop used the post-increment option, while the second for loop used pre-increment instead. The total number of iterations was 10,000,000. Here are the results:
Post-increment: 2.148 seconds
Pre-increment: 1.692 seconds
Time saved: 0.456 seconds; 21.23%
7. Regular Expressions for input validation?
It is always a good idea to try and avoid regular expressions, where possible and practical. There are functions in PHP which will do exactly what some regular expressions do, but faster. Take this example:
if(ereg('[0123456789]', $number)) {
// Is integer
}else{
// Is not integer
}
It is much faster to do this instead:
if(ctype_digit($number)) {
// Is integer
}else{
// Is not integer
}
To test this, I used ereg('[0123456789]', $number) 1,000,000 times, followed by using ctype_digit($number) 1,000,000 times. Here are the results:
Regular Expressions: 2.401 seconds
ctype_digit: 0.985 seconds
Time saved: 1.416 seconds; 58.98%
8. split() or explode()
The split() function supports regular expressions, while explode() does not. It is often faster to use explode() when you do not need to use regular expressions.I done yet another test. I used split() to split a string without regular expression requirements, and then used explode() to split the same string. I repeated this 1,000,000 times. My results are:
split(): 5.453 seconds
explode(): 3.556 seconds
Time saved: 1.897 seconds; 34.79%
9. Use time() rather than date('U')
When you want to get the current Unix timestamp, it is faster to use time() rather than date('U'). To test this, I used the time() function 100,000 times, followed by date('U') 100,000 times. My results are as follows:
date('U'): 19.162 seconds
time(): 0.057 seconds
Time saved: 19.105 seconds; 99.7%
10. Fastest type of loop
In PHP, there are a number of loops available for you to use. There are while loops, do-while loops, and for loops. To see which one of these were fastest, I used each of them to perform 100,000,000 iterations. These are the loops which I used:
while(++$a<100000000){}
for(;++$a<100000000;){}
do{}while(++$a<100000000)
Here are my results:
while(++$a<100000000){}: 15.519 seconds
for(;++$a<100000000;){}: 17.577 seconds
do{}while(++$a<100000000): 13.744 seconds
As you can see, my results show that a do-while loop is 21.81% faster, compared to a for loop.
