Combine writematrix with a text header and safe as file
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Hi guys,
I am stuck with this problem since many hours. I want have multible *.IV0 files (with headers). I attached one example AS A *.TXT! It was npt possible to upload *.IV0 files. So please rename it when you try to solve this problem. The fact that it is a *.IV0 file changes many things. Since with this filetype it is not possible to use some matlab codes.
I try to average all files in a specifc folder excluding the header (first 27 rows). This works great so far. Afterwards I wanted to save the averaged data by using writematrix. This works too by using following code:
folder = 'C:\Users\--__aver\';
IV0Files = dir(fullfile(folder, '*.IV0')); % Use absolute path names
numfiles = length(IV0Files);
data_sum = 0;
rows = [1,2,3,4];
for ci = 1:numfiles
data_file = readmatrix(IV0Files(ci).name,"NumHeaderLines",27,"FileType","text");
data_sum = data_sum+data_file(:,rows); % summation accross the files (removed 3rd column (time))
end
% divide by numfiles to have the average (and not the sum)
average = data_sum/numfiles;
averagecell=num2cell(average);
%this is to save the data in the new IV0 file
writematrix(average, fullfile(folder,'otherdirectionSK-ITOLspray16.IV0'),"Delimiter","tab", "FileType", "text");
But now comes the heavy part. I tried to add a header to my output file. The header should be the same as in one of the files I average. So basically the first 27 rows of the attached file. I tried soo much and I can´t figure out a way to do it. Since it is a *.IV0 file things get even more complicated. I have tried things using:
opts (does not work for *.IV0)
fgets (in a for loop (same as code above), got stuck, I think because of the tab delimiter maybe...)
3 Comments
dpb
on 4 Jan 2021
The high-level writeXXX routines don't have the ability to be able to append data to or to be used to append data to existing text files, so that's a non-starter.
Probably the easiest way in coding would be to hold the header lines in a temporary file and then just use the OS copy command to concatenate the two.
There's no reason I can think of why the fgets/fprintf combination wouldn't work; show the code for it as you tried it...note, however, that you can't combine it with writematrix; you'll have to use all low-level i/o functions.
I think the restriction of not having an append option is a real limitation in the general usefulness of the new functions.
Simon Keegan
on 4 Jan 2021
Simon Keegan
on 4 Jan 2021
Accepted Answer
Mathieu NOE
on 4 Jan 2021
hello simon
welcome back and happy new year !
I somehow recognize this code.... and now comes the upgraded version that appends the data to the headers
try this ( after adjusting the folder path) :
folder = cd;
% folder = 'C:\Users\--__aver\';
IV0Files = dir(fullfile(folder, '*.IV0')); % Use absolute path names
numfiles = length(IV0Files);
data_sum = 0;
rows = [1,2,3,4];
for ci = 1:numfiles
data_file = readmatrix(IV0Files(ci).name,"NumHeaderLines",27,"FileType","text");
data_sum = data_sum+data_file(:,rows); % summation accross the files (removed 3rd column (time))
end
% divide by numfiles to have the average (and not the sum)
average = data_sum/numfiles;
% averagecell=num2cell(average); % not needed as we use writematrix
% retrieve headers line (from first file)
lines= readlines(IV0Files(1).name);
header_lines = convertStringsToChars(lines(1:27,:));
%this is to save the data in the new IV0 file
writecell(header_lines, fullfile([folder '\out'],'otherdirectionSK-ITOLspray16.IV0'),"Delimiter","tab", "FileType", "text");
writematrix(average, fullfile([folder '\out'],'otherdirectionSK-ITOLspray16.IV0'),"Delimiter","tab", "FileType", "text","WriteMode","append");
9 Comments
Simon Keegan
on 4 Jan 2021
Simon Keegan
on 4 Jan 2021
Mathieu NOE
on 4 Jan 2021
yeah, I find those extra " a bit annoying
I tried two versions of my code ,
first attempt was :
second is the one I sent you with
header_lines = convertStringsToChars(lines(1:27,:));
writecell(header_lines,....
but both gives the same unpleasant output with added "
maybe Walter (the genius of all geniuses in the entire universe - sorry for the others guys) as the trick for that
i'll be glad to learn that one too !
Mathieu NOE
on 4 Jan 2021
sorry , sometimes my pc will not react on time
so my first attempt was :
header_lines = lines(1:27,:);
writematrix(header_lines,....
Mathieu NOE
on 4 Jan 2021
and both results are the same
looking into writematrix and writecell was not successfull to get rid of those "
doc says only if original strings contain double quote , this can be converted optionnally to two single quote , but I don't think it will do any good there.
Simon Keegan
on 4 Jan 2021
Mathieu NOE
on 4 Jan 2021
VICTORY
I was wrong and this works :
replace last lines with :
%this is to save the data in the new IV0 file
writecell(header_lines, fullfile([folder '\out'],'otherdirectionSK-ITOLspray16.IV0'),"Delimiter","tab", "FileType", "text","QuoteStrings",0);
writematrix(average, fullfile([folder '\out'],'otherdirectionSK-ITOLspray16.IV0'),"Delimiter","tab", "FileType", "text","WriteMode","append");
Simon Keegan
on 4 Jan 2021
Mathieu NOE
on 4 Jan 2021
you're welcome !!
pretty happy to start the new year on a good tempo ! at least that worked today !!
More Answers (1)
Walter Roberson
on 4 Jan 2021
Edited: Walter Roberson
on 23 Aug 2022
0 votes
'writemode', 'append'
2 Comments
dpb
on 4 Jan 2021
Interesting new addition, Walter.
Which release introduced it? R2019b lacks it which is what have here...
Alan Hoskins
on 23 Aug 2022
Yeah, 2019b lacks this functionality. I guess I need to upgrade.
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