Data Types integer, float, boolean, string, array, object, resource, NULL Variable Declarations $variablename = <value>; $anothervariable =& $variablename; (Assign by Reference) Declare Array $arrayname = array(); Initialize Array $arrayname = array(<value1>, <value2>, <value3>); $arrayname = array(<key> => <value>, <key> => <value>); (Define Keys) $multiarray = array(<key> => array(<value1>,<value2>)); (Multi-dimensional) Common Array Functions sort(<array>); (Sort array assigns new keys) asort(<array>); (Sort array maintain keys) rsort(<array>); (Sort array in reverse, new keys) arsort(<array>); (Sort array in reverse, maintain keys) count(<array>); (Count elements) count(<array>,COUNT_RECURSIVE); (Count multidimensional array) array_push(<array>,<value>); (Push item onto end of array) array_pop(<array>