// raw array output
print_r($arr);
// the above well-formatted
echo '<pre>'; print_r($array); echo '</pre>';
// more details like datatype and length
var_dump($arr);
// output that PHP understands
var_export($arr);
// by foreach loop
foreach($arr as $key=>$value)
echo $key, '=>', $value; // $value must be convertible to string