PHP tip: Comma Separated Values (CSV) List to Array and Array to CSV List

// create a comma separated list from an array 
$array = array('green','purple','blue','yellow','amber','red'); 
$comma_separated = implode(",", $array); 
echo $comma_separated; 

// create an array from a comma separated list 
$list = "green, purple, blue, yellow, amber, red"; 
$array = explode(',', $list); 
print_r($array);