MATLAB: Set union of different ‘datetime’ columns

datetimeset union

Hello guys,

I got a dataset in excel which I imported as a table. There are a plenty of parameters in it with each parameter has its own time column. I also selected all time columns as datetime-variables.

My goal now is to bring all the time columns together in order to have one time column and a plenty of parameter columns that are still on their refering time point. Plotting of this modified dataset would be way nicer than before.

How do I achieve this goal?

Thank you for your help in advance!

Kind regards, Spacey

Best Answer

If understood correctly, you have several columns which are datetime and you want to regroup them in just one column.

In that case, use stack.

Related Solutions

MATLAB: Matlab imported excel time format change

Assuming the date and time is stored as char arrays in both columns:

dt = datetime(strcat(column1, ' ', column2), ...
              'InputFormat', 'dd/MM/yyyy hh:mm:ss.SSS', ...
              'Format', 'yyyy-MM-dd hh:mm:ss.SSS')

If you want it back as char arrays:

char(dt)

MATLAB: How to subtract ‘datetime’ from ‘datetime’ in MATLAB GUI

The problem is converting to strings instead of just comparing...

What will work to compute the offset including DST if in effect is--

v=now;                  % return the local current time as datenum(*)
t1=datetime(v,'ConvertFrom','datenum','TimeZone','America/New_York','Format','d-MMM-y HH:mm:ss Z');
t2=datetime(v,'ConvertFrom','datenum','TimeZone','Africa/Khartoum','Format','d-MMM-y HH:mm:ss Z');
u=t2-t1
u = 
duration
 -7:00:00

The above sets the local time a variable before calling the conversion factors to ensure there isn't a rollover between the two calls to datetime that would introduce a small error in the result if were to occur.

(*) Interesting shortcoming that TMW hasn't introduced a datetime-aware routine to parallel the old standby that returns a datenum.

ADDENDUM

An alternative would be to use the timezones table data--

A=timezones('Africa');            % get the Africa table
N=timezones('America');           % and Americas, too
Z1=N(contains(N.Name,'New_York'); % retrieve TZ of specific interest
Z2=A(contains(A.Name,'Khartoum');
u=Z2.UTCOffset+Z2.DSTOffset-(Z1.UTCOffset+Z1.DSTOffset) % offset including DTS
u =
   7

The problem with this is that I don't believe the table will update the DTS offset with time of year; it's just the value used in the location. So, this is probably not viable actual solution lacking a test for whether DST is in effect in both locations at the time of interest.

Best Answer

Related Solutions

MATLAB: Matlab imported excel time format change

MATLAB: How to subtract ‘datetime’ from ‘datetime’ in MATLAB GUI

Related Question