.csv Date and Time assigned Data Import

Hi dear Community,

I need to import csv data from Trials into MATLAB. The dataset is as follows:

2016/11/02 17:51:54,017;256,451812744141;0;0;0,130208298563957

I tried to achieve the import with csvread, but I guess, matlab cannot handle date and time in one cell?! Another problem may be, that the decimal delimiter symbol is ',' and not '.'. Actually, I don't need the date, I only need the time and the difference of the time between adjacent measurements as an additional column.

Help is very appreciated, thanks therefore in advance! Best Wishes, Georg

Answer 1

[Jeremy Hughes]

Hi George,

If you're using R2016b you can import this directly, but it will take a little bit of configuration The following should work:

opts = detectImportOptions(yourfilename,'Delimiter',';') 
opts.VariableTypes = {'datetime','double','double','double','double'};
opts = setvaropts(opts,1,'InputFormat','yyyy/MM/DD HH:mm:ss,SSS');
opts = setvaropts(opts,2:5,'DecimalSeparator',',');
T = readtable(yourfilename,opts)

[Georg Söllinger]

Oh perfect, this works very fine!! In the meantime, I tried to achieve a solution with the editor and excel, but this solution is definitely more elegant!

 Thank you all for your answers.

Answer 2

[dbmn]

Hi Georg,

if you already extracted the required string, it can easily be converted into a datetime variable using a custom inputformat (that is also capable of dealing with commas)

mytimevar = datetime('2016/11/02 17:51:54,017', 'InputFormat', 'yyyy/MM/DD HH:mm:ss,SSS');

if you still need to extract the string I may suggest stringsplit

[Georg Söllinger]

Thanks for your answer dbmn, but it is only half the answer.

Well, as said, matlab throws an error if I make the csv import.

The code is as follows:

data = csvread('20161102_R05_1.csv',';',1);

and the resulting error (yes, I have skipped the header!)

Error using dlmread (line 138)
HeaderLines must be integer-valued.

Error in csvread (line 47)
    m=dlmread(filename, ',', r, c);

Error in Tool_Carrier_Motion_Trial (line 10)
data = csvread('20161102_R05_1.csv',';',1);

[dbmn]

I just checked with a csv-file that i created by copying your example line 5 times.

Here is what I found

• csvread gives you the error you specified (most likely due to the fact, that the file is not "real csv" due to the additional commas
• one solution is to use readtable

 data = readtable('20161102_R05_1.csv');

• Another possibility with more control is to use textscan

fid = fopen('20161102_R05_1.csv','r');
data={};
while ~feof(fid)
data(end+1,:) = textscan(fid, '%s%s%s%s%s', 1, 'delimiter',';');
end
fclose(fid);