A = readmatrix('filename.xlsx');
len = size(A,1);
% Make sure array length is divisible by 17.
B = padarray(A,[17-mod(len,17), 0],NaN,'post');
% Reshape each column
wid = size(B,1)/17;
C(:,1:3:3*wid) = reshape(B(:,1),17,wid);
C(:,2:3:3*wid+1) = reshape(B(:,2),17,wid);
% Clear out the zeros in between columns
C(:,3:3:end) = nan;
% Write to file
writematrix(C,'newfile.xlsx')
Is this what you mean?
