Inserting a column of repeated values

I have the following table

T2 =

  3557×3 table

       Date        Time (Hours)    Total Rainfall(mm)
    ___________    ____________    __________________

            NaT           NaN                1       
    03-Mar-2019      10:00:00             0.51       
    03-Mar-2019      11:00:00                0       
    03-Mar-2019      12:00:00                0       
    03-Mar-2019      13:00:00                0       
    03-Mar-2019      14:00:00                0       
    03-Mar-2019      15:00:00             1.27       
    03-Mar-2019      16:00:00                0       
    03-Mar-2019      17:00:00                0       
    03-Mar-2019      18:00:00             1.02       
            NaT           NaN                2       
    11-Mar-2019      17:00:00              3.3       
            NaT           NaN                3       
    12-Mar-2019      18:00:00             1.78       
    12-Mar-2019      19:00:00             1.78       
    12-Mar-2019      20:00:00             0.51       
    12-Mar-2019      21:00:00                0       
    12-Mar-2019      22:00:00            11.17       
            NaT           NaN                4       

I would like to insert a column stating the number of hours between the NaN. It should look like:

            T2 =

  3557×3 table

       Date        Time (Hours)      No.of Hours   Total Rainfall(mm)
    ___________    ____________     ___________   __________________

            NaT           NaN                         1       
    03-Mar-2019      10:00:00         1              0.51       
    03-Mar-2019      11:00:00         2               0       
    03-Mar-2019      12:00:00         3               0       
    03-Mar-2019      13:00:00         4               0       
    03-Mar-2019      14:00:00         5               0       
    03-Mar-2019      15:00:00         6              1.27       
    03-Mar-2019      16:00:00         7               0       
    03-Mar-2019      17:00:00         8               0       
    03-Mar-2019      18:00:00         9              1.02       
            NaT           NaN                         2       
    11-Mar-2019      17:00:00         1              3.3       
            NaT           NaN                         3       
    12-Mar-2019      18:00:00         1             1.78       
    12-Mar-2019      19:00:00         2             1.78       
    12-Mar-2019      20:00:00         3             0.51       
    12-Mar-2019      21:00:00         4              0       
    12-Mar-2019      22:00:00         5           11.17       
              

Answer 1

[Akira Agata]

How about the following method?

% Sample data
load('outdoors.mat');
T = timetable2table(outdoors);
T.Humidity([1, 6, 15]) =  NaN; % Put some NaNs

% Create group ID
idx = isnan(T.Humidity);
group = cumsum(idx);

% Apply cumsum for each group
NumOfHours = splitapply(@(x){cumsum(x)}, ~idx, group);
NumOfHours = cell2mat(NumOfHours);
NumOfHours(idx) = NaN;

% Add and move the column
T.NumOfHous = NumOfHours;
T = movevars(T, 'NumOfHous', 'After', 'Humidity');

% Show the result
disp(T)

           Time            Humidity    NumOfHous    TemperatureF    PressureHg
    ___________________    ________    _________    ____________    __________

    2015-11-15 00:00:24       NaN         NaN           51.3          29.61   
    2015-11-15 01:30:24      48.9           1           51.5          29.61   
    2015-11-15 03:00:24      48.9           2           51.5          29.61   
    2015-11-15 04:30:24      48.8           3           51.5          29.61   
    2015-11-15 06:00:24      48.7           4           51.5           29.6   
    2015-11-15 07:30:24       NaN         NaN           51.5           29.6   
    2015-11-15 09:00:24        49           1           51.5           29.6   
    2015-11-15 10:30:24      49.1           2           51.3           29.6   
    2015-11-15 12:00:24      49.1           3           51.3          29.61   
    2015-11-15 13:30:24      49.1           4           51.5          29.61   
    2015-11-15 15:00:24      48.9           5           51.5          29.61   
    2015-11-15 16:30:24        49           6           51.5          29.61   
    2015-11-15 18:00:24        49           7           51.3          29.61   
    2015-11-15 19:30:24      48.9           8           51.3           29.6   
    2015-11-15 21:00:24       NaN         NaN           51.2          29.61   
    2015-11-15 22:30:24      48.9           1           51.1          29.61   
    2015-11-16 00:00:24      48.7           2           51.2          29.61   
    2015-11-16 01:30:24      48.6           3           51.3          29.61   
    2015-11-16 03:00:24      48.4           4           51.5          29.61   
    2015-11-16 04:30:24      48.3           5           51.6          29.61   
    2015-11-16 06:00:24      47.7           6           51.6          29.61   
    2015-11-16 07:30:24      47.9           7           51.6          29.61   
    2015-11-16 09:00:24      48.2           8           51.6          29.61   
    2015-11-16 10:30:24        48           9           51.6          29.61   
    2015-11-16 12:00:24      47.9          10           51.6          29.61   
    2015-11-16 13:30:24      47.8          11           51.6          29.61   
    2015-11-16 15:00:24      47.9          12           51.5          29.61   
    2015-11-16 16:30:24      47.6          13           51.6          29.61   
    2015-11-16 18:00:00      47.6          14           51.6          29.61   
    2015-11-16 18:00:24      47.7          15           51.6          29.61   
    2015-11-16 19:30:24      47.5          16           51.6          29.61   
    2015-11-16 21:00:24      47.6          17           51.8          29.62   
    2015-11-16 22:30:24      47.3          18           51.8          29.62   
    2015-11-17 00:00:24      47.8          19           51.8          29.61   
    2015-11-17 01:30:24        48          20           51.6          29.62   
    2015-11-17 03:00:24      47.9          21           51.6          29.62   
    2015-11-17 04:30:24        48          22           51.6          29.62   
    2015-11-17 06:00:24      48.1          23           51.6          29.61   
    2015-11-17 07:30:24      48.1          24           51.5          29.62   
    2015-11-17 09:00:24      48.3          25           51.2          29.62   
    2015-11-17 10:30:24      48.5          26           51.1          29.61   
    2015-11-17 12:00:24      48.4          27           51.1          29.61   
    2015-11-17 13:30:24      48.5          28           51.1          29.61   
    2015-11-17 15:00:24      48.5          29           51.2          29.61   
    2015-11-17 16:30:24      48.6          30           51.2          29.61   
    2015-11-17 18:00:24      48.7          31           50.9          29.61   
    2015-11-17 19:30:24        49          32           50.8          29.61   
    2015-11-17 21:00:24      49.3          33           50.8          29.61   
    2015-11-17 22:30:24      49.5          34           50.7          29.61   
    2015-11-18 00:00:24      49.5          35           50.8          29.61   
    2015-11-18 01:30:24      49.5          36           50.8          29.61   

[Queena Edwards]

I made some changes based on my code but this works. Thank you so much!