PHP

Refactoring some client code the other day I found a lot of inefficient logic. Whilst this example is written in PHP the concept is applicable in other programming languages.

Many people use for loops in the belief that they are faster than a foreach, and while this is often the case it can be slower and less flexible if you make some simple mistakes. Consider the following:

A slow FOR loop

$text="thequickbrownfoxjumpsoverthelazydog";
for($i=0; $i < strlen($text); $i++){ // Loop through the characters
echo ( substr($text,$i,1) == 'o' ) ? "Its an o" : "Not an o"; // Display true or false as relevant
}

A faster FOR loop

$text="thequickbrownfoxjumpsoverthelazydog";
$length = strlen($text); // obtain length of the string
for($i=0; $i < $length ; $i++){ // Loop through the characters
echo ( substr($text,$i,1) == 'o' ) ? "Its an o" : "Not an o"; // Display true or false as relevant
}

The second loop is faster because it does not evaluate the string length each time the loop runs strlen($text) as in the first example. Small differences like this can have a large effect on the speed of scripts especially if there are many loops or iterations.

All URLs on Gravatar are based on the use of the hashed value of an email address. According to their best practice you should:

1. Trim leading and trailing whitespace from an email address
2. Force all characters to lower-case
3. md5 hash the final string

Of course in PHP this is trivial as the following function shows:

function fetchGravatar() {
$fetchHash = md5(strtolower(trim('your_email.address.com')));
$GravatarImage = 'http://www.gravatar.com/avatar/' . $fetchHash;
return $GravatarImage;
}

Profiles are also available if you require them.

Alternating row colours within a grid of data can make for a more pleasant viewing experience and has become a popular styling method in recent times. I was a little incredulous at some code I saw recently to determine alternating rows so without further introduction, meet the Modulo operator which is a quick and easy way to get up and running:

for($i=0;$i<10;$i++){ if($i % 2){ // This is an even row }else{ // This is an odd row } }

I'm sure you will be able to apply this to your own css or styling within your loops.