$arr = array('a"aa',array("c'd",array('e"f')));
function changes($arr){
 foreach($arr as $k=>$v){
 if (is_string($v)){
  $arr[$k] = addslashes($v);
 }else if (is_array($v)) { //若为数组，则再转义.
  $arr[$k] = changes($v);
 }
 }
 return $arr;
}
print_r(changes($arr));