create multidimensional array with n depth

Hi all: I've been trying to create a multidimensional array with n depth in php. Tried to use a recursive function passing array references by pointers but seems like it's not possible or I still don't understand this subject enough. Finally managed to get it going using the eval function. The code below converts a seperated string into a multi dimensional array with n depth: e.g. $array['1_20-2_16-7_14'] = 12 will become $eval_array[1][20][2][16][7][14] = 12 foreach(array_keys($this->quantity_array) AS $key){ if($this->quantity_array[$key] > 0){ $combinations = explode('-', $key); $eval_string = '$eval_array'; foreach(array_keys($combinations) AS $key2){ $option_key_value = explode('_', $combinations[$key2]); $eval_string .= '['.$option_key_value[0].']['.$option_key_value[1].']'; } $eval_string .= ' = '.$this->quantity_array[$key].';'; eval($eval_string); } } Using eval() for it seems a bit expensive to me. So I've been wondering if there is an easier way? TIA Gunter