--TEST-- Test array_diff_key() function : usage variation - Passing float indexed array --FILE-- '0', 10 => '10', -10 => '-10', 20 =>'20', -20 => '-20'); $float_indx_array = array(0.0 => '0.0', 10.5 => '10.5', -10.5 => '-10.5', 0.5 => '0.5'); echo "\n-- Testing array_diff_key() function with float indexed array --\n"; // loop through each element of the array for arr1 var_dump( array_diff_key($input_array, $float_indx_array) ); var_dump( array_diff_key($float_indx_array, $input_array) ); ?> ===DONE=== --EXPECT-- *** Testing array_diff_key() : usage variation *** -- Testing array_diff_key() function with float indexed array -- array(2) { [20]=> string(2) "20" [-20]=> string(3) "-20" } array(0) { } ===DONE===