how can i plot Time and Date from cell class (workspace)?

I have an EEG Data from Muse. the data is in .csv In this case i want to plot magnitude over time. the magnitude is a number which have values to be plotted, but the time data(column) in excel is a cell class(workspace), which is String type. as example : '2017-09-16 15:44:14.803' is there any function I can use to plot date and time?

Answer 1

[Cam Salzberger]

Hello Hasbian,

It's pretty easy to convert cell arrays of character arrays into datetimes, and then plot from there. In the case of irregular datetime character arrays, you simply have to tell datetime how to interpret them with the 'InputFormat' parameter:

c = {'2017-09-16 15:44:14.803' ; '2017-09-16 15:45:15.804'};
dt = datetime(c, 'InputFormat', 'yyyy-MM-dd HH:mm:ss.SSS')

If you use readtable to pull the data in though, you may be able to do this all in one step. See the link for an example.

-Cam

[Peter Perkins]

And just to be clear, once you have a datetime vector and a numeric vector, you can just plot them:

plot(dt,x)

On the other hand, you might find it more useful to plot EEG data against elapsed time, so perhaps something like

et = dt - dt(1); % or whatever base time is appropriate
et.Format = 's';
plot(et, x)