why I am having this "Cell contents assignment to a non-cell array object."error?

I am trying to store Approximation vector of every image in a CSV file , so that every column or every row in the CSV file represents an image, but I have this error and don't know how to fix it Cell contents assignment to a non-cell array object.

Cell contents assignment to a non-cell array object.
  Error in haarallwave (line 100)
  data{i}= [A1vec];

here is my code

      srcFiles = dir('E:\sense\process\*.jpg');  % the folder in which ur images exists
        for i = 1 : length(srcFiles)
            filename = strcat('E:\sense\process\',srcFiles(i).name);

        [X1,map]=imread(filename);
        map=gray(256);
        [c,s]=wavedec2(X1,3,'haar');
        [H1,V1,D1] = detcoef2('all',c,s,1);
        A1 = appcoef2(c,s,'haar',1);
        V1img = wcodemat(V1,255,'mat',1); %wcodemat just for display
        H1img = wcodemat(H1,255,'mat',1);
        D1img = wcodemat(D1,255,'mat',1);
        A1img = wcodemat(A1,255,'mat',1);
        [H2,V2,D2] = detcoef2('all',c,s,2);
        A2 = appcoef2(c,s,'haar',2);
        V2img = wcodemat(V2,255,'mat',1);
        H2img = wcodemat(H2,255,'mat',1);
        D2img = wcodemat(D2,255,'mat',1);
        A2img = wcodemat(A2,255,'mat',1); 
      subplot(2,2,1);
        imshow(A1img);
        colormap(map);
        title('Approximation Coef. of Level 1');

        subplot(2,2,2);
        imagesc(H1img);
        title('Horizontal detail Coef. of Level 1');

        subplot(2,2,3);
        imagesc(V1img);
        title('Vertical detail Coef. of Level 1');

        subplot(2,2,4);
        imagesc(D1img);
        title('Diagonal detail Coef. of Level 1');

        figure;
        subplot(2,2,1);
        imagesc(A2img);
        colormap(map);

        title('Approximation Coef. of Level 2');

        subplot(2,2,2)
        imagesc(H2img);
        title('Horizontal detail Coef. of Level 2');

        subplot(2,2,3)
        imagesc(V2img);
        title('Vertical detail Coef. of Level 2');

        subplot(2,2,4)
        imagesc(D2img);
        title('Diagonal detail Coef. of Level 2');

        [H3,V3,D3] = detcoef2('all',c,s,3);
        A3 = appcoef2(c,s,'haar',3);

        V3img = wcodemat(V3,255,'mat',1);
        H3img = wcodemat(H3,255,'mat',1);
        D3img = wcodemat(D3,255,'mat',1);
        A3img = wcodemat(A3,255,'mat',1);

        figure;
        subplot(2,2,1);
        imagesc(A3img);
        colormap(map);

        title('Approximation Coef. of Level 2');

        subplot(2,2,2)
        imagesc(H3img);
        title('Horizontal detail Coef. of Level 2');

        subplot(2,2,3)
        imagesc(V3img);
        title('Vertical detail Coef. of Level 2');

        subplot(2,2,4)
        imagesc(D3img);
        title('Diagonal detail Coef. of Level 2');

        %A1vec = reshape(A1img,prod(size(A1img)),1);
        %figure;
        %imshow(log(abs(A1img)),[]), colormap(jet), colorbar
        A1vec=reshape(A1img,1,[]);

        magImage = abs(A1img).^2;
        energy = sum(magImage(:))

        data{i}= [A1vec];

        end

        csvwrite('csvlistenergy31113.dat',data)

Answer 1

[dpb]

data must be an existing array of double or other non-cell type already.

clear data

before beginning the script.

[Hadeer tawfik]

Thank you soo much