How do I insert Nan values into a list, if there isn't a file which has a specific name? when exporting column values of multiple files into new file.

Hello,

I am new to Matlab. I am working on one year output data of a detector. I faced problems regarding the data processing procedure. Since then I have been learning matlab.

I have continuously named 365 output files such as 20140101 , 20140102 .... 20140110 (in format of YYYYMMDD) . Each files have same structure as follows :

# comment
# comment
# comment
# comment
# comment
# comment
# comment
# comment
# comment
# comment
# comment
# comment
# comment
# Time (UTC)    nV
20140109T000000 006.55
20140109T000030 006.58
20140109T000100 006.60
20140109T000130 006.62
20140109T000200 006.66
...

I need to export values of nV from all output files into one new file in a order. nV has 2880 values. So i need to make new text file which has 1051200 x 2 array data. However, some output files are missing. For examle, lets say i need to plot 10 day datas, however the detector didn't work on the 6th and 8th day so there will be only 8 datas. But since I need to plot time dependant graphic, if there is no output file i want to insert some NaN values or 0 into the new file where nVs are exported. So I was wondering if it is possible?

What I need is a file wich has stucture as follows:

1   006.55 (nV of 20140101)
    006.58
    ...
2   007.59 (nV of 20140102)
    007.61
    ...
3   nV of 20140103
    ...
4   nV of 20140104
    ...
5   nV of 20140105
    ...   
6   0 (since there is no output file as 20140106)
    0
    ...
7   nV of 20140107
    ...
8   0 (since there is no output file as 20140108)
    0
    ...
9   nV of 20140109
    ...
10  nV of 20140110
    ...    

I have attached 10day sample datas.

Answer 1

[Sulaymon Eshkabilov]

The data (nV) import and augmentation from the data files can be done using readmatrix(), strcat(). E.g.:

DS =[];
for ii = 1:5
    FN = strcat(num2str(20140100+ii), '.txt');
    D = readmatrix(FN);
    DS = [DS; D(:,2)];
end
D7 = readmatrix('20140107.txt');
D9 = readmatrix('20140109.txt');
D10 = readmatrix('20140110.txt');
DS = [DS; D7(:,2); D9(:,2); D10(:,2)];

[Nar Gomboo]

Thank you for the answer. I have so many outputs files not only ten. So I need some automation script which reads a file name and copyies the nV value to new text file.

[Sulaymon Eshkabilov]

You should use a code as shown here:

P = 'Directory to where the files are stored';
% P=pwd;   % Current directory
S = dir(fullfile(P, '*.txt'));  % Select the file extension to suit your data files
D = 0;
for k = 1:numel(S) 
    F = fullfile(P, S(k).name);
    D = D + readmatrix(F);                
end
DS = D(:,2);   % ALL numerical data of nV taken out