php - Difference between var_dump,var_export & print_r -

what difference between var_dump, var_export , print_r ?

var_dump debugging purposes. var_dump prints result.

// var_dump(array('', false, 42, array('42'))); array(4) {   [0]=> string(0) ""   [1]=> bool(false)   [2]=> int(42)   [3]=> array(1) {[0]=>string(2) "42")} } 

print_r debugging purposes, too, not include member's type. it's idea use if know types of elements in array, can misleading otherwise. print_r default prints result, allows returning string instead using optional $return parameter.

array (     [0] =>     [1] =>     [2] => 42     [3] => array ([0] => 42) ) 

var_export prints valid php code. useful if calculated values , want results constant in script. note var_export can not handle reference cycles/recursive arrays, whereas var_dump , print_r check these. var_export default prints result, allows returning string instead using optional $return parameter.

array (   0 => '',   2 => false,   2 => 42,   3 => array (0 => '42',), ) 

personally, think var_export best compromise of concise , precise.