MATLAB: How to extract specific data from multiple .mat files

extract multiple values

Hi there,
I have 134 .mat files (sessions). Each file (session) contains 10 stations. Each station contains 24 values (hourly value) for each file. I need to extract those values from 134 .mat files. I use loop, however, matlab always shows "Unable to perform assignment because the indices on the left side are not compatible with the size of the right side."
if loadf==1
   for ip = 1: ns % number of sessions
     
       nstat = length(x_.antenna);
        sres = std(res.mainVal);
        for k = 1:nstat
            stnam = x_.antenna(k).name;
            if strcmp(stnam,'KATH12M ')||strcmp(stnam,'HART15M ')||strcmp(stnam,'YARRA12M')||strcmp(stnam,'HOBART26')||strcmp(stnam,'WARK12M ')||strcmp(stnam,'ONSALA60');
                if strcmp(stnam,'KATH12M ')
                    id = 1;
                    mjd_KATH(ip) = x_.zwd(k).mjd; 
                    zwd_KATH(ip) = x_.zwd(k).val;
                    dzwd_KATH(ip) = x_.zwd(k).mx;
                end
                if strcmp(stnam,'HART15M ')
                    id = 2;
                    mjd_HART(ip) = x_.zwd(k).mjd;
                    zwd_HART(ip) = x_.zwd(k).val;
                    dzwd_HART(ip) = x_.zwd(k).mx;
                end
                if strcmp(stnam,'YARRA12M')
                    id = 3;
                    mjd_YARRA(ip) = x_.zwd(k).mjd;
                    zwd_YARRA(ip) = x_.zwd(k).val;
                    dzwd_YARRA(ip) = x_.zwd(k).mx;
                end
                if strcmp(stnam,'HOBART26')
                    id = 4;
                    mjd_HOBART(ip) = x_.zwd(k).mjd;
                    zwd_HOBART(ip) = x_.zwd(k).val;
                    dzwd_HOBART(ip) = x_.zwd(k).mx;
                end
                if strcmp(stnam,'WARK12M ')
                    id = 5;
                    mjd_WARK(ip) = x_.zwd(k).mjd;
                    zwd_WARK(ip) = x_.zwd(k).val;
                    dzwd_WARK(ip) = x_.zwd(k).mx;
                end
                if strcmp(stnam,'ONSALA60')
                    id = 6;
                    mjd_ONSA(ip) = x_.zwd(k).mjd;
                    zwd_ONSA(ip) = x_.zwd(k).val;
                    dzwd_ONSA(ip) = x_.zwd(k).mx;
                end
            end
        end
    end
end

Best Answer

You need to think about how you want to store your data. The code below will store everything in a cell array, but it would probably make a lot more sense to but the data in a 2D array or something. I will leave the further processing to you. I removed the id lines, as they get overwriten and don't seem to play any role.
if loadf==1
    mjd_KATH=cell(1,ns);
    zwd_KATH=cell(1,ns);
    dzwd_KATH=cell(1,ns);
    %repeat this for the other antennas
    
   for ip = 1: ns % number of sessions
     
       nstat = length(x_.antenna);
        sres = std(res.mainVal);
        for k = 1:nstat
            switch x_.antenna(k).name%whenever you have many ifs, consider using switch instead
                case 'KATH12M '
                    mjd_KATH{ip} = x_.zwd(k).mjd; 
                    zwd_KATH{ip} = x_.zwd(k).val;
                    dzwd_KATH{ip} = x_.zwd(k).mx;
                case 'HART15M '
                    mjd_HART{ip} = x_.zwd(k).mjd;
                    zwd_HART{ip} = x_.zwd(k).val;
                    dzwd_HART{ip} = x_.zwd(k).mx;
                case 'YARRA12M'
                    mjd_YARRA{ip} = x_.zwd(k).mjd;
                    zwd_YARRA{ip} = x_.zwd(k).val;
                    dzwd_YARRA{ip} = x_.zwd(k).mx;
                case 'HOBART26'
                    mjd_HOBART{ip} = x_.zwd(k).mjd;
                    zwd_HOBART{ip} = x_.zwd(k).val;
                    dzwd_HOBART{ip} = x_.zwd(k).mx;
                case 'WARK12M '
                    mjd_WARK{ip} = x_.zwd(k).mjd;
                    zwd_WARK{ip} = x_.zwd(k).val;
                    dzwd_WARK{ip} = x_.zwd(k).mx;
                case 'ONSALA60'
                    mjd_ONSA{ip} = x_.zwd(k).mjd;
                    zwd_ONSA{ip} = x_.zwd(k).val;
                    dzwd_ONSA{ip} = x_.zwd(k).mx;
                otherwise
                    error('unknown antenna')
            end
        end
    end
end
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