Creating text file by combining/editing header and data

Hello,

I have two different type of file with different headers sizes and different number of variables.

Fisrt one can be used by the software I have but not the second one.

First one has a 34 lines header and 8 column of data

Second one has 64 header line and 5 column of data

I want to edit/generate a readable file from the second type of file.

First : I want to recover the header from the first file

 fid=fopen('file');
 size_max=0;
 
 for i=1:34
     
%      line(i,:)=fgets(fid);
     temp=size(fgets(fid),2);
     size_max=max(temp, size_max);
 end

frewind(fid);
 
 line=char(' '*ones(34,size_max));
 
 for i=1:34
     temp=fgets(fid);
     
     line(i,1:size(temp,2))=temp;
     
 end
 

By doing so I get the header but I also get extra characters (arrows and carriage return)

How can a get a proper header (without extra character) ?

After doing that I want to recover data from second file. (I have a 30 line header and 5 rows of data) I use this command

 datacell = textscan(fid2,'%f %f %f %f %f','headerline', 30,'Delimiter',',');

I obtain a cell which is 1x5 and which contains 1024x1 double in each row.

I am adding several column this way to make it a 1x8 cell with 1024x1 double column

 comp={double(zeros(1024,1))}; %column of zeros I want to add
datacell2={[datacell comp comp comp] }; % datacell is the original data, 1x5 cell

Finally, how can I merge the header and the data into one txt file ?

I think I will use the cellwrite function (available on file exchange) but I'm not sure how to do that correctly...

Thank you for your help

PS : Sorry but I can't share the file.

[dpb]

Well, without at least a description of the actual file format it's imponderable...even if you don't think you can upload an actual file (and the reasons folks think that are rarely truly relevant) you can attach a sample with dummy data of the correct format. This needs to include the proper data types for each variable in the input/output files.

Which release of MATLAB are you using? Unless it's now getting to be pretty old, there should be no reason to need any FEX contributions.

Answer 1

[dpb]

N1=34;                          % file1 header length -- don't bury magic constants inside code
N2=64;                          % file2 header length
hdr=readlines('File1.txt');     % read the file
hdr=hdr(1:N1);                  % keep the header lines only
data=readmatrix('file2.txt','NumHeaderLines',N2);   % get data from second
data=[data zeros(size(data,1),3)];                  % augment with three extra columns
data=join(string(data),',');                        % convert to string array
writematrix([hdr;data],'outputfile.txt')            % and write a new output file

[Nicolas]

Thank you for your help.

I tried with this code

 N1=34; %header size                         
N2=60;            %header size  2
hdr=readlines('example1.txt');     % read the file for header
hdr=hdr(1:N1);                  % get header
data=readmatrix('example2.txt','NumHeaderLines',N2);   % get data
data=[data zeros(size(data,1),3)];                  % augment with three extra columns
data=join(string(data),',');                        % convert to string array
writematrix([hdr;data],'outputfile.txt')            % and write a new output file

It is working well but I got extra double quote at the beginning and end of each lines.

How can I remove them ?

[dpb]

Use, 'QuoteStrings',0 in the writematrix call -- see writematrix for details...

[Nicolas]

Thank you a lot for your help !