MATLAB: How to copy data from one timetable to another

MATLABtabletimetabletimetables

Hi all,
I have three timetables (called Tmin, Tmax, Prec) with daily meteorological variables at two measurement sites (Site 1 and Site 2; I will come back to Site 3 in a moment). The data are from 1st July 2018 to now. Here an example of the Prec timetable:
  353×3 timetable
            time            Site_1    Site_2    Site_3
    ____________________    ______    ______    ____
    01-Jun-2018 00:00:00     0.2       0.2      NaN 
    02-Jun-2018 00:00:00       0         0      NaN 
    03-Jun-2018 00:00:00       0         0      NaN 
    ...
I'm trying to add data from a public weather station (Site 3, currently all NaNs) for the same period. These data are available online in monthly csv files which I import in a loop into monthly timetables:
30×3 timetable
       Date       MinimumTemperature__C_    MaximumTemperature__C_    Rainfall_mm_
    __________    ______________________    ______________________    ____________
    2018-06-01             4.1                       13.3                   0     
    2018-06-02             3.5                       13.6                 0.2     
    2018-06-03             4.3                       13.8                   0
What I'm trying to do is to copy Site 3 data from each monthly timetable into a respective row in column 3 of my main timetables (Tmin, Tmax, Prec).
1) Is there a simple function to do that?
2) Is it a problem that the date format isn't the same? If so, how can I change it?
Many thanks in advance for help!

Best Answer

Is there a simple function to do that?
Yes: synchronize()
Is it a problem that the date format isn't the same?
As long as they are in datetime format, it shouldn't be a problem.
There should be a way to specify that you want to merge the rainfall column of the second timetable (TT2) with the site_3 column of the first timetable (TT1) but after a brief search I haven't found that method (please leave comments if anyone finds it!). Alternatively you can:
  1. remove the unnecessary columns from TT2
  2. change the name of the rainfall column to "Site_3"
  3. remove the "Site_3" column from TT1
  4. Merge the two cleaned-up time tables.
That would look something like this:
% Remove columns in 2nd timetable that shouldn't be merged with table 1
TT2clean = removevars(TT2,{'MinimumTemperature__C_','MaximumTemperature__C_'});
% Rename Rainfall column to "Site_3"
TT2.Properties.VariableNames = strrep(TT2.Properties.VariableNames,'Rainfall_mm_','Site_3'); 
% Remove Site_3 from first timetable
TT1clean = removevars(TT1,'Site_3'); 
% Synchronize timetables
TT = synchronize(TT1clean,TT2clean);
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