combine double array question

Hello,

Im trying to get data from a COM port from a arduino and conveting it to a double.The goal is collect 1023 samples and store them in a array like, 5X1023, or 27X1023,12X1023,etc..... And ive tried y = [D y]; and y = [D; y];.....heres the simple code:and ive been using assignin only to show results and wont be used in final code. Please dont cruicify me.

Edit: so if a value passes a threshold get the next X samples and store them ....

s = serial('COM9');
assignin('base','s',s);

fopen(s);
j = 1;

i = 1;



thesh = 0;
countDown = 0;
strUp = 1;
d = [];
D= [];
n=1;
x = [];
y = [];


%begin contuious loop,in loop check each value,if a value passes
%a threshold,get next X samples!

%turn on loop upon startup
while(strUp == 1)
    
    %check data from COM port of arduino
    x = fscanf(s);
   
    celldata(j) = cellstr(x);
    d= str2double(celldata);
    disp(celldata(j));
    
    assignin('base','x',x);
    assignin('base','d',d);
    
    
    assignin('base','j',j);
    
    pause(0.01);
    %if value passed threshold,store next X samples
    if(thesh == 1)
        while(countDown >= 1)
            x = fscanf(s);
           
            celldata(j) = cellstr(x);
            D= str2double(celldata);
            
            j = j + 1;
            disp(j);
            
            
            assignin('base','j',j);
             assignin('base','celldata',celldata);
            pause(0.01);
            countDown = countDown - 1;
            
            if(countDown == 1) && (j == 1024)
               
                                assignin('base','y',y);
             
                y = [D; y];
                assignin('base','x',x);
                assignin('base','D',D);
                thesh = 0;
                countDown = 0;
                j=1;
                d= 1;
            end
            
            
        end
        
    end
    
    %if data exceeds a threshold trigger recording
    if (d > 1500 || d < 1000) && (thesh == 0)
        %if triggered turn on bool that controls storage of wanted values
        
        
     
        j = 1;
        thesh = 1;
        countDown = 1024;
        
        
    end
end

[Bob Thompson]

What exactly is your question for us? What are you looking for help with?

[m j]

Great question. So how do i store data in a manner like "a" X 1024 were "a" can be 1,5,12,134,1546,`32444,etc.....Ive stated and tried storing my data from coverting str2double and then tried to store the data as stated above, eg..."a" X 1024.

[Bob Thompson]

How are you determining the size of 'a'? I understand that it can be variable, but what conditions specify that variability?

[m j]

I dont care about size of "a", size of a can be whatever it wants to be,within the while loop. Once threshold is passed get next X samples. "a" X 1024 ,only thing that matters is the 1024 data samples I collect. Edit:specify the variability? I dont understand this sorry.

[m j]

examples :

a = zeros(1,8);

b = zeros(1,8);

c = [a; b];

equals = c 2 X 8

[Bob Thompson]

If you don't care about the number of rows, then why not just index with a colon as the row index. This will select all rows, no matter what size your array is. You can specify the column size separately to only include values you want.

C = A(:,1:1024);

If this isn't what you are looking for then I am obviously confused. Can you be more specific with reference to your code. Which variables are you hoping to make a certain size (I did not see 'a' anywhere in your code as a variable. str2double was used to create D, but I'm not sure what you're trying to do with it.