how to add header for new output file?

greeting matlab expert, I have multiple meteorological data in txt format and the content just like below

2.11           METEOROLOGICAL DATA                     RINEX VERSION / TYPE
teqc  2018Jun8                          20180904 15:17:08UTCPGM / RUN BY / DATE
Linux 2.6.32-573.12.1.x86_64|x86_64|gcc -static|Linux 64|=+ COMMENT
cjem                                                        MARKER NAME
     7    PR    TD    HR    WS    WD    RI    HI            # / TYPES OF OBSERV
                                                  0.0    PR SENSOR MOD/TYPE/ACC
                                                  0.0    TD SENSOR MOD/TYPE/ACC
                                                  0.0    HR SENSOR MOD/TYPE/ACC
                                                  0.0    WS SENSOR MOD/TYPE/ACC
                                                  0.0    WD SENSOR MOD/TYPE/ACC
                                                  0.0    RI SENSOR MOD/TYPE/ACC
                                                  0.0    HI SENSOR MOD/TYPE/ACC
        0.0000        0.0000        0.0000        0.0000 PR SENSOR POS XYZ/H
                                                            END OF HEADER
 18  4 25  2 57  0    0.0    0.0    0.0    0.0    0.0    0.0    0.0
 18  4 25  2 57 30 1001.6   29.9   62.1    0.0    0.0    0.0    0.0
 18  4 25  2 58  0 1001.6   30.0   62.2    0.0    0.0    0.0    0.0
 18  4 25  2 58 30 1001.6   30.0   61.5    0.0    0.0    0.0    0.0
 18  4 25  2 59  0 1001.6   30.0   61.4    0.0    0.0    0.0    0.0
 18  4 25  2 59 30 1001.5   30.0   61.9    0.0    0.0    0.0    0.0
 18  4 25  3  0  0 1001.5   30.0   61.9    0.0    0.0    0.0    0.0

The first six column below header are date time and I try to convert it to modified juliandate. This is my script

clc;clear; close all;
input_folder = 'E:\Data\data';
files = dir(fullfile(input_folder, '*.txt'));
file_paths = fullfile({files.folder}, {files.name});
nfile = numel(file_paths);
for i = 1 : nfile
    data=  readmatrix(file_paths{i},'NumHeaderLines',15);% a display of data in a single file
    data(:,end)=[];
    data(:,1) = data(:,1)+2000; %add year
T1 = array2table(data(:,7:end)); %main data
DT = datetime(data(:,1:6)); %datetime
jd = juliandate(DT); %Juliandate
MJD = jd - 2400000.5; %Modified Juliandate
T1 = addvars(T1,MJD,'before','Var1');
% % TT1 = table2timetable(T1);
% % TT1rt = retime(TT1,'daily','mean');
% % TT2 = timetable2table (TT1rt);
t=T1(:,:);
c=table2cell(t);
newdata = [c];
writecell (newdata,file_paths{i},'Delimiter','space');
end

how can I write new converted txt file with the header on?

Answer 1

[Jan]

You want to copy the header? Read the first 15 lines and write it:

[fid, msg] = fopen(file_paths{i}, 'r');
assert(fid > 0, msg);
Head = cell(1, 15);
for k = 1:15
    Head{k} = fgetl(fid);
end
fclose;

[fid, msg] = fopen(theNexFile, 'w');
assert(fid > 0, msg);
fprintf(fid, '%s\n', Head{:});

Use 'WriteMode', 'append' in writecell afterwards.

Note: newdata = [c] is exactly the same as: newdata = c. [] is Matlab's operator for concatenation. [c] concatenates c with nothing.

[adhi dermawan]

hehe I forgot to change that line. thank you sir