$sites = array ("google.com", "yahoo.com", "php.net", "apple.com");
$k = array_rand($sites);
echo $sites[$k];

Get rid of HTML tags in paragraph. Mostly use in CMS

$message = "<div> This is my bio </div>";
echo strip_tags($message); // "This is my bio"

Function 3: strftime

This function change type of date, time as we want

strftime("%B %d, %Y", time()); // July 28, 2012

Function 4: basename

Get only  a file name.

$path = "/some/long/path/to/the/special_file.txt";
$filename1 = basename($path); // special_file.txt
$filename2 = basename($path, ".txt"); // special_file

Function 5: list

Re-assign variable in an array

$array = ["Ellery", "Queen"];
list($first-name, $last-name) = $array;
echo $first-name; // Ellery
echo $last-name; // Queen

Function 6: range

Create an array which contains characters or numbers

range(100, 110); // array(100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 10)
range('g', 'l'); // array('g', 'h', 'i', 'j', 'k'. 'l');

Function 7: isset

The most common and useful funciton to check variable existed or not.

$name = "Joe";
isset($name); // return true
isset($age); // return false