how to write the results from the code into the csv file format?

Hi,

Code below is producing the result including dates format and I usually use dlmwrite to write the results in csv format but in this case I am getting an error below: (What should I change so I can save the results)

Error:

Error using sprintf

Unable to convert 'duration' value to 'double'.

Error in dlmwrite (line 161)

str = sprintf(format,m(i,:));

Error in ploting_timeoverUy (line 30)

dlmwrite('Uy_timestamps.csv',[dates,all_Uy])

Code:

close all; clear all; clc;
projectdir = 'F:\3-PIV_Experimental_Data\Outlet_110\Data_LaserSheet_D\Data_PIV\5-AverageFilter_VelocitiesExtration\Point_Velocities\Uy';
files = dir( fullfile(projectdir, '*', '*.csv') );
filenames = fullfile({files.folder}, {files.name});
num_files = length(filenames);
all_Uy = zeros(num_files,1);
all_time = zeros(num_files,1);
for i = 1:numel(files)
    filename = filenames{i};
    data = readmatrix(filename);
    all_Uy(i) = data(1,2);
end

Location = 'F:\3-PIV_Experimental_Data\Outlet_110\Data_LaserSheet_D\Data_PIV\5-AverageFilter_VelocitiesExtration\Point_Velocities\Uy';
files = dir(Location);
dirFlags = [files.isdir];
subFolders = files(dirFlags); 
subFolderNames = {subFolders(3:end).name} 
for k = 1 : length(subFolderNames)
    fprintf('Sub folder #%d = %s\n', k, subFolderNames{k});
end
dates = extractBetween(subFolderNames,"Run ",".");
dates = replace(dates,'-',':');
dates = duration(dates,"InputFormat","hh:mm:ss")
dates=dates'

plot(dates,all_Uy, '-*');
dlmwrite('Uy_timestamps.csv',[dates,all_Uy])

Answer 1

[Cris LaPierre]

I'd try using writematrix instead.

[muhammad choudhry]

hi chris I tried using writematrix([dates,all_Uy],'M.csv'), but it did not save the data properly please see the file M.csv attached intead data should be save as shown in the file TimeStamps_Uy.xlsx( I copy and pasted the data from the work space in this file)...... I am searching how to save it in a write format but no success so far!

[Cris LaPierre]

Ah, you have two different data types. You'll have to use writetable instead.

[muhammad choudhry]

Hi I have tried that as well:

writetable([dates,all_Uy],'myData.csv')

getting this error:

Error using writetable (line 183)

Unsupported type 'duration'. Use writematrix instead.

Error in ploting_timeoverUy (line 32)

writetable([dates,all_Uy],'myData.csv')

[Cris LaPierre]

The error is because you are trying to create a matrix by concatenating a duration with a double.

[dates,all_Uy]

All values in a matrix must be of the same data type. You will need to first create a table. Try this (untested).

myT = table(dates,all_Uy,'VariableNames',["TimeStamp","Uy"])
writetable(myT,'myData.csv') 

[muhammad choudhry]

cheers, that worked and thanks for the explanation. I will remember that " all the matrix values has to be in the same datatype"

[Image Analyst]

That's for dlmwrite and csvwrite(). For tables, each column can be different, or for max flexbility, you can use fprintf() like I showed below in my answer.

Answer 2

[Image Analyst]

You could do it manually with fprintf():

fid = fopen(fileName, 'wt');
if fid == -1
    warningMessage = sprintf('Error opening file for output:\n%s', fileName);
    uiwait(errordlg(warningMessage));
    return;
end
for k = 1 : length(all_Uy)
    fprintf(fid, '%s, %f\n', dates(k), all_Uy(k));
end
fclose(fid)

I'm not sure about the dates format. You may have to make sure the dates value matches the format specifier. If it's a string, %s will work.