Error in using NaN value and calculate the mean of each row

I have file that has a different number of column in each row. Than i had to calculate the mean value of each row start from column 4 to end of column. I used this script but still facing some errors

clear;
clc;
format short;

f = dir('D:\full_Data_Cryosat_c2p0004.txt');
A=1:length(f);
D = f(A).name;
readlines = @(f)regexp(fileread(f),'\r?\n','split');
data=readlines(D);

for k=1:size(data,1)
    qdata=[];
    kelompok=data(k,:);
    index=arrayfun(@(kelompok),'uniformoutput',false);

Invalid expression. When calling a function or indexing a variable, use parentheses. Otherwise, check for mismatched delimiters.

    qdata=kelompok(index,1);
        
    sigma=std(qdata(:,4:end));
    rata2=mean(qdata(:,4:end));
    batas_atas=rata2+3*sigma;
    batas_bawah=rata2-3*sigma;
    id_qc=find(qdata(:,4:end)>=batas_bawah & qdata(:,4:end)<=batas_atas);
    qdata_qc=qdata(id_qc,:);
    
    exp_data = [];
    for i=1:size(qdata,1)
        waktu = sprintf('%d/%d/%d',qdata_qc(i,4),qdata_qc(i,5),qdata_qc(i,6));
        exp_data = [exp_data; {num2str(qdata_qc(i,1)) num2str(qdata_qc(i,2)) num2str(qdata_qc(i,3)) waktu num2str(k)}];
    end
    exp_data = [header; exp_data];
    file_name = ['Msl_.txt'];
    dlmwrite(file_name, exp_data, 'delimiter', '\t');
    
end

thankss

Answer 1

[Image Analyst]

Did you try mean():

rowMeans = mean(data(:, 4:end), 2, 'omitnan');