find out negative values and specific values, take it out, record those negative and specific values into a text file

given a (52560 x 8 double)

I need to find out the negative values from the last 3 columns, and if the value is 70% more than the sum of last 3 values and next 3 values

then replace the value with the sum of last 3 values and next 3 values divided by 6.

then record those values into a log file(txt file) (X x 3 matrix)

[Mathieu NOE]

hello

this looks like a homework

what have you done so far ?

[zhi cheng]

I just started doing it, I just done combine data from 3 txt file into 1 matrix, and split the variables.

so far this part, I have no idea how to do it

[Image Analyst]

If it's homework, see this:

How do I get help on homework questions on MATLAB Answers? - MATLAB Answers - MATLAB Central

Answer 1

[Ghazwan]

The following code should do it. Note that because of the rules you have, you have to skip the first and the last three row.

A=[52560 x 8];
X=zeros(1,3);
for ii=4:length(A(:,1))-3
    NValues=zeros(1,3);
    for jj=1:3
        Sum1=sum(A(ii-3:ii-1,5+jj))+sum(A(ii+1:ii+3,5+jj));
        Value= (A(ii, 5+jj)-Sum1)/A(ii, 5+jj);
        if A(ii, 5+jj)<0 && Value>0.7
            NValues(1,jj)=A(ii,5+jj);
            A(ii,5+jj)=Sum1/6;
        end
    end
    if sum(abs(NValues))~=0,  X=[X;NValues]; end
end
if length(X(:,1))>1, X=X(2:end,:); end
xlswrite('Values.xlsx',X,1);