--TEST-- Test array_map() function : usage variations - built-in function as callback --FILE-- <?php /* Prototype : array array_map ( callback $callback , array $arr1 [, array $... ] ) * Description: Applies the callback to the elements of the given arrays * Source code: ext/standard/array.c */ /* * Test array_map() by passing buit-in function as callback function */ echo "*** Testing array_map() : built-in function ***\n"; $array1 = array(1, 2, 3); $array2 = array(3, 4, 5); echo "-- with built-in function 'pow' and two parameters --\n"; var_dump( array_map('pow', $array1, $array2)); echo "-- with built-in function 'pow' and one parameter --\n"; var_dump( array_map('pow', $array1)); echo "-- with language construct --\n"; var_dump( array_map('echo', $array1)); echo "Done"; ?> --EXPECTF-- *** Testing array_map() : built-in function *** -- with built-in function 'pow' and two parameters -- array(3) { [0]=> int(1) [1]=> int(16) [2]=> int(243) } -- with built-in function 'pow' and one parameter -- Warning: pow() expects exactly 2 parameters, 1 given in %s on line %d Warning: pow() expects exactly 2 parameters, 1 given in %s on line %d Warning: pow() expects exactly 2 parameters, 1 given in %s on line %d array(3) { [0]=> NULL [1]=> NULL [2]=> NULL } -- with language construct -- Warning: array_map() expects parameter 1 to be a valid callback, function 'echo' not found or invalid function name in %s on line %d NULL Done