How to filter dataset into specific time range and scan for missing values?

Hi there,

I got a large set of measured data in a text file with 3 hour time intervals. Here some measurements are not recorded and some time values are not in a sequence.

I need to delete the time intervals which are not in the sequence and then add some value for missing time intervals.

I have tried with the 'unique' matlab function, but failed to achieve it. Hereby attached the sample file of the dataset.

I would greatly appreciate if anyone can help me to achieve this.

Thank you.

Answer 1

[Peter Perkins]

Timetables and retime were born to do this:

>> X = [89 2 03 0030 1.6955 5.08; ...
        89 2 03 0330 1.8172 4.39; ...
        89 2 03 0630 1.2139 4.15; ...
        89 2 03 0830 1.1986 4.33; ...
        89 2 03 0930 0.9349 4.37; ...
        89 2 03 1230 0.9610 4.17; ...
        89 2 03 2130 0.8554 4.39];
>> time = datetime(1900+X(:,1),X(:,2),X(:,3),fix(X(:,4)/100),X(:,4)-100*fix(X(:,4)/100),0);
>> tt = timetable(X(:,4),X(:,5),'RowTimes',time)
tt =
  7×2 timetable
            Time            Var1     Var2 
    ____________________    ____    ______
    03-Feb-1989 00:30:00      30    1.6955
    03-Feb-1989 03:30:00     330    1.8172
    03-Feb-1989 06:30:00     630    1.2139
    03-Feb-1989 08:30:00     830    1.1986
    03-Feb-1989 09:30:00     930    0.9349
    03-Feb-1989 12:30:00    1230     0.961
    03-Feb-1989 21:30:00    2130    0.8554
>> time3 = time(1):hours(3):time(end);
>> tt3 = retime(tt,time3,'fillwithmissing')
tt3 =
  8×2 timetable
            Time            Var1     Var2 
    ____________________    ____    ______
    03-Feb-1989 00:30:00      30    1.6955
    03-Feb-1989 03:30:00     330    1.8172
    03-Feb-1989 06:30:00     630    1.2139
    03-Feb-1989 09:30:00     930    0.9349
    03-Feb-1989 12:30:00    1230     0.961
    03-Feb-1989 15:30:00     NaN       NaN
    03-Feb-1989 18:30:00     NaN       NaN
    03-Feb-1989 21:30:00    2130    0.8554