php – how to assign a key to an array within another array?

Good I have this code in my controller (it is in mvc).

function update_format_valuations ()
    {
         $ id = $ _POST['id'];
         $ before = $ _POST['antes'];
       // echo $ id;
        // print_r ($ id);
        print_r (implode (',', (array) $ _ POST['data']));

            $ data = implode (',', (array) $ _ POST['data']);

            $ data = str_replace ("[","",$data);
            $data = str_replace("]"," ", $ data);
            $ data = str_replace ("" "," '", $ data);

            $ comments = array (
                'form_obser_1' => $ _POST['observaciones1'],
                'form_obser_2' => $ _POST['observaciones2'],
                'form_obser_3' => $ _POST['observaciones3'],
                'form_obser_4' => $ _POST['observaciones4'],
                'form_obser_5' => $ _POST['observaciones5'],
                'form_obser_6' => $ _POST['observaciones6'],
                'form_obser_7' => $ _POST['observaciones7'],
                'form_obser_8' => $ _POST['observaciones8'],
                'form_obser_9' => $ _POST['observaciones9'],
                'form_obser_10' => $ _POST['observaciones10'],
                'form_area_1' => $ _POST['check1'],
                'form_area_2' => $ _POST['check2'],
                'form_area_3' => $ _POST['check3'],
                'form_area_4' => $ _POST['check4'],
                'form_area_5' => $ _POST['check5'],
                'form_area_6' => $ _POST['check6'],
                'form_area_7' => $ _POST['check7'],
                'form_area_8' => $ _POST['check8'],
                'form_area_9' => $ _POST['check9'],
                'form_area_10' => $ _POST['check10'],
                'form_area_11' => $ _POST['check11'],
                'form_area_12' => $ _POST['check12'],
                'form_area_13' => $ _POST['check13'],
                'form_area_14' => $ _POST['check14'],
                'form_area_15' => $ _POST['check15'],
                'form_area_16' => $ _POST['check16'],
                'form_area_17' => $ _POST['check17'],
                'form_area_18' => $ _POST['check18'],
                'form_area_19' => $ _POST['check19'],
                'form_area_20' => $ _POST['check20'],
                'form_area_21' => $ _POST['check21'],
                'form_area_22' => $ _POST['check22'],
                'form_area_23' => $ _POST['check23'],
                'form_area_24' => $ _POST['check24']

        );

            $ data2 = array_push ($ data, $ comments);


            $ updata = array (
            "date_cot_av" => date ('Y-m-d'),
            "client_cot_av" => $ _POST['clientec'],
            "tec_id_cot_av" => $ _POST['tecnicoc'],
            "unit_cot_av" => $ _POST['unidadc'],
            "ven_id_cot_av" => $ _POST['vendedorc'],
            "serie_cot_av" => $ _POST['seriec'],
            "km_cot_av" => $ _POST['kilometrajec'],
            "des_trab_cot_av1" => $ _POST['descripcion1'],
            "des_trab_cot_av2" => $ _POST['descripcion2'],
            "des_trab_cot_av3" => $ _POST['descripcion3'],
            "des_trab_cot_av4" => $ _POST['descripcion4'],
            "des_trab_cot_av5" => $ _POST['descripcion5'],
            "des_trab_cot_av6" => $ _POST['descripcion6'],
            "des_trab_cot_av7" => $ _POST['descripcion7'],
            "price_cot_av1" => $ _POST['precio1'],
            "price_cot_av2" => $ _POST['precio2'],
            "price_cot_av3" => $ _POST['precio3'],
            "price_cot_av4" => $ _POST['precio4'],
            "price_cot_av5" => $ _POST['precio5'],
            "price_cot_av6" => $ _POST['precio6'],
            "price_cot_av7" => $ _POST['precio7'],
            "total_cot_av1" => $ _POST['total1'],
            "total_cot_av2" => $ _POST['total2'],
            "total_cot_av3" => $ _POST['total3'],
            "total_cot_av4" => $ _POST['total4'],
            "total_cot_av5" => $ _POST['total5'],
            "total_cot_av6" => $ _POST['total6'],
            "total_cot_av7" => $ _POST['total7'],
            "sub_tot_cot_av" => $ _POST['total'],
            "iva_cot_av" => $ _POST['iva'],
            "total_neto_cot_av" => $ _POST['totalNeto']
        );

        // $ this-> db-> insert ('quote_avaluo_resultado', $ insert);



            // print_r ($ data);
           $ result = $ this-> valuations-> update_format_valuations ($ data2, $ updata, $ id, $ before);

    }

my $ data is an array with 120 records of 1 or 0, I keep those 120 records in a table plus those in my other array $ comments, my other array $ updata it is stored in another table.

My question is how can I assign the cell (key) to the array that comes in $ data, this is to make an update, I already did it with an insert and it was easier, it was just

insert into 'table' ('column_1' .... 'column_120') value (". $ data.")

and it was everything but now in this case it is an update but I do not know how to do it or if I am wrong with something, I have corrected it but it marks me error 404 Not Found