Using timetable versus tscollection objects

I have Simulink models that log signal data using the Simulink.SimulationData.Dataset class.

I'm writing post-processing m-code that helps analyze model outputs and would like to combine the data into either a tscollection object or a timetable object, which is easier to deal with than the collection of Simulink.SimulationData.Signal objects contained in the logsout object generated by the Simulink model.

There doesn't seem to be an 'easy' way to convert the signals in logsout into a timetable object, whereas one can create a tscolleciton object rather easily:

tsCol = tscollection;
for ii=1:logsout.numElements
     tsCol = tsCol.addts(logsout.getElement(ii).Values);
end

MathWorks seems to really be pushing the use of timetables through functions such as stackedplot, and tscollection objects seem to be something of an afterthought.

It there an easy way to convert a tscollection object into a timetable? Failing that, is there a way to create an empty timetable and add the signal data from the Dataset signals in a loop as shown above?

Answer 1

[Corey Silva]

Hi Alan,

Below is a toy example where you have a timeseriescollection containing two timeseries, ts1 and ts2.

>> ts1 = timeseries(rand(5,1),'Name','ts1');
>> ts2 = timeseries(rand(5,1),'Name','ts2');
>> tsc = tscollection({ts1,ts2});
>> tt = timetable(seconds(tsc.Time),tsc.ts1.Data(:),tsc.ts2.Data(:),'VariableNames',{'ts1_Data','ts2_Data'})
tt =
  5×2 timetable
    Time     ts1_Data    ts2_Data
    _____    ________    ________
    0 sec    0.15761     0.14189 
    1 sec    0.97059     0.42176 
    2 sec    0.95717     0.91574 
    3 sec    0.48538     0.79221 
    4 sec    0.80028     0.95949 

Hopefully this gives you enough to get started with using timetables. I would like to assure you that we are actively working on solutions to converting between timeseries objects and timetables for future releases of MATLAB.

[Alan Bindemann]

Corey,

Thanks for your reply. For what its worth, in my use case I have dozens of elements in my Simulink.SimulationData.Dataset class, so the form you propose doesn't scale very well, unless I resort to an eval statement to build up the timetable command.

The lack of methods on the timetable class to add and remove elements is something that would be very useful. I'm surprised it doesn't already exist.

Regards,

Alan Bindemann

[Corey Silva]

Hi Alan,

The addvars and removevars functions can be used to add and remove variables respectively from existing timetables. I hope this helps.

Corey

[Alan Bindemann]

Thanks, That helps a lot. The code below is close to doing what I want.

for ii=1:logsout.numElements
    elemTs = logsout.getElement(ii).Values;
    if ~isempty(elemTs.DataInfo.Units)
        Units{ii} = elemTs.DataInfo.Units.Name;
    else
        Units{ii} = '';
    end
    Names{ii} = elemTs.Name;
    if ii==1
        tTable = timetable(seconds(elemTs.Time), elemTs.Data);
    else
        tTable = addvars(tTable, squeeze(elemTs.Data));
    end
end
tTable.Properties.VariableUnits = Units;
tTable.Properties.VariableNames = Names;

I recommend that the MathWorks mentions the addvars and removevars functions in the documentation for timetable.

Regards,

Alan Bindemann