Store data into an Array or variable

BELOW is a part of my codes. ARDUNIO - MATLAB.

PROBLEM: I want to store all values of P, Q and V in every update of the loop so that it would now be easy for me to print it to excel using xlswrite.

CAN SOMEONE HELP ME WITH THIS. Or any alternative to store the data for DATA ACQUISITION FOR MY STUDY. your answers are a great help.

while strcmp(start,'DISCONNECT')

            RxText = fscanf(serConn);
            RxText = strtrim(RxText);
            disp(RxText);
            pause(0.5)

            %%%%%%%for data acquisition
            handles.counter = handles.counter + 1;

            [InRange,power,va,var,pf,volt,current,id]=strread(RxText,'%s%s%s%s%s%s%s%s','delimiter',',');

                %%%MAIN POWER ANALYZER
                if strcmp(id,'B') %DATA FOR MAIN PA
                set(handles.LP4,'String',power);
                set(handles.LQ4,'String',var);
                set(handles.LV4,'String',volt);

                    %%%%CONVERT STRING TO DOUBLE %%%%%%
                    P4= str2double(power);
                    Q4 = str2double(var);
                    V4 = str2double(volt);

                    %%%%CONDITION SET TO LOAD MAIN STAT
                    if P4>70 && P4<80
                        set(handles.STAT4,'String','WARNING');
                    elseif P4>80
                        set(handles.STAT4,'string','SYSTEM OVERLOAD');
                    else
                        set(handles.STAT4,'string','NORMAL');
                    end

                    %%%%%DATA ACQUISITION %%%%%
                    P4(handles.counter,1) = P4
                    %Q4(handles.counter,2) = Q4;
                    %V4(handles.counter,3) = V4;

                   % data = [P1 Q1 V1]

                end

Answer 1

[Walter Roberson]

count = 0;   %before loop

Inside the loop,

count = count + 1;
data(count, :) = [P1 Q1 V1];

[Jovanie Josol]

Thanks for this. I will try and comment again what is the result.

[Jovanie Josol]

I HAVE A PROBLEM ENCOUNTERED. the data that will be stored will have zero. 3 zeros. I used 4 Power analyzers and used multiplexing. so i think y the zeros exist. HOW CAN I OMIT THE ZEROS??

data =

         0         0         0
    7.2000   84.3000  212.9900
         0         0         0
         0         0         0
         0         0         0
    7.2000   84.3000  212.9100
         0         0         0
         0         0         0
         0         0         0
    7.2000   84.3000  212.8600
         0         0         0
         0         0         0
         0         0         0
    7.2000   84.8000  213.1800

Answer 2

[Jovanie Josol]

Got it! I put the code data(count,:) = [P1 P2 P3 P4] outside the if end condition. then what

                P1 = get(handles.LP1,'string');
                P2 = get(handles.LP2,'string');
                P3 = get(handles.LP3,'string');
                P4 = get(handles.LP4,'string');

                P1=str2double(P1);
                P2=str2double(P2);
                P3=str2double(P3);
                P4=str2double(P4);

                data(count,:) = [P1 P2 P3 P4]