Eliminating and creating new data file

Hello all, I have data which has information for different events, each event has 5 row information. I just want to eliminate this data and delete all of 5 line for that event with respect to some criteria and to create new data file without eleminated data.

A = xlsread('example.xls');
M = cell(1, length(4:5:size(A,1))); %Preallocate M for speed
Miso = cell(1,length(4:5:size(A,1))); %Preallocate Miso for speed
isoratio = cell(1,length(4:5:size(A,1))); %Preallocate isoratio for speed 
j = 1; q=1; v=1;
for i= 4:5:size(A,1) 
    Mrr=A(i,2)*10^A(i,1);
    Mtt=A(i,4)*10^A(i,1);
    Mpp=A(i,6)*10^A(i,1);
    Mrt=A(i,8)*10^A(i,1);
    Mrp=A(i,10)*10^A(i,1);
    Mtp=A(i,12)*10^A(i,1);
%%%build the given full moment tensor%%%
    M{j} = [Mrr Mrt Mrp; Mrt Mtt Mtp; Mrp Mtp Mpp]; 
    Miso{q}=(trace(M{j}/3)*eye(3,3));
    isoratio{v} = norm(Miso{q},'fro')/(norm(M{j},'fro'));
j = j + 1;
q = q + 1; 
if isoratio{v} > 10e-17;
       fprintf('isoratio > 10e-17 \n');
    end
   v = v + 1;
end

For example in this case I defined isoratio for each event, and the program should delete all 5 line information about that event and write 5 line information of each event with isoratio value bigger than 10e-17 to new xlsx or txt file.

Is there any advice for this code ? I attached data file to this post. Thanks in advance for your interest.

[Stephen23]

Original question and answer:

https://www.mathworks.com/matlabcentral/answers/403026-how-to-eliminate-and-create-new-data-file

[Gökçe Öter]

Yes, but this one is not the same with the former one. In this case for loop is considered and calculation is the critical part to save new data file which I couldn't achieve :)

Answer 1

[Jan]

An advice:

Compare:

    Mrr=A(i,2)*10^A(i,1);
    Mtt=A(i,4)*10^A(i,1);
    Mpp=A(i,6)*10^A(i,1);
    Mrt=A(i,8)*10^A(i,1);
    Mrp=A(i,10)*10^A(i,1);
    Mtp=A(i,12)*10^A(i,1);
    M{j} = [Mrr Mrt Mrp; Mrt Mtt Mtp; Mrp Mtp Mpp];

with

    index = [2, 8, 10; 8, 4, 12; 10, 12, 6];  % Before the loop

    M{j} = reshape(A(i, index), 3, 3) *10^A(i,1);

length(4:5:size(A,1)) is a waste of time. Use this once:

len = floor((size(A, 1) - 4) / 5) - 1