How can I extract the time column of a timetable

Asked by Antonio Melieni on 20 Apr 2019

Latest activity Commented on by Peter Perkins on 3 May 2019

Accepted Answer by Andrei Bobrov

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Hi,

I need to extrct the time column of a timetable as I need to manipulate it.

any Ideas?

3 Comments

David Wilson on 20 Apr 2019

Look at the help file for timetable. You should be able to access the 1st column with the dot notation.

Following example is straight from the help file.

MeasurementTime = datetime({'2015-12-18 08:03:05';'2015-12-18 10:03:17';'2015-12-18 12:03:13'});
Temp = [37.3;39.1;42.3];
Pressure = [30.1;30.03;29.9];
WindSpeed = [13.4;6.5;7.3];
WindDirection = categorical({'NW';'N';'NW'});
TT = timetable(MeasurementTime,Temp,Pressure,WindSpeed,WindDirection)

Now reference as

>> TT.MeasurementTime
ans = 
  3×1 datetime array
   18-Dec-2015 08:03:05
   18-Dec-2015 10:03:17
   18-Dec-2015 12:03:13

You could of course convert to a (normal) table, or even an array.

Antonio Melieni on 20 Apr 2019

what I needed was array.Time;

Peter Perkins on 3 May 2019

Just for the record, David was correct, except for one subtle point: the row times in a timetable are metadata, not one of the variables. You can access them by name in exactly the same way, though.

David created his timetable with a workspace variable named MeasurementTime, whose name the timetable picked up; that's why his row times were named Measurement time. The default name is Time, though.

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MATLAB and Simulink Student Suite

1 Answer

Link

Answer by Andrei Bobrov on 20 Apr 2019

Edited by Andrei Bobrov on 20 Apr 2019

Accepted Answer

variant

a = rand(20,6);
date1 = datetime(2019,4,19) + hours(cumsum(70*rand(20,1)));
TT = array2timetable(a,'RowTimes',date1);
date_out = TT.Time;

1 Comment

Antonio Melieni on 20 Apr 2019

thats it :)

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MATLAB and Simulink Student Suite

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