Arrays

// Make an array with unique values from a comma delimited string
$array = array_unique(explode(',',$string));
 
// Compare array1 to array2 and remove common values
$array = array_diff($array1, $array2);
 
// Randomise order of the array elements
shuffle($array);
 
// Sort array in natural order then reverse
natsort($dl);
$dl = array_reverse($dl, false);
 
Numeric arrays
 
// Make an array over a number range
$array  = range(1,100);
 
// Make an array over a number range stepped by 10
$array  = range(1,100,10);