How to merge two timetables with different data and time?

Hi everyone, I had a nice and clean time table that I had to extract some sections of it for calculations during different hours of day. For example Jan to May 10 to 14 and 0 to 10 and 14 to 00. Now I have three time tables from the extracted one. I want to merge them again so that I will have one clean timetable with only one column of data rather than 3 columns with NaN (that what I am getting). Also, [T1;T2] is not working and retrns the following error:

All tables in the bracketed expression must have the same number of rows.

[Adam Danz]

If you're trying one of these methods listed in the link below and it isn't working for you, provide more detail including error messages and samples from your table (using head()).

https://www.mathworks.com/help/matlab/matlab_prog/combine-timetables-and-synchronize-their-data.html

[Wolfgang McCormack]

@Adam Danz thank you! I actually read them all and applied some but none are working for my case. So I had huge annual data with 5 minute intervals. I extracted some specific dates and their corresponding value (second column - if you know any easy way for this please let me know) and then I multiplied those values by some other values. Now they are section by section, for example, March 20 to April 13 and then April 14 to Dec 20. I used a concept in that page which literally replaces NaN of one huge timetable with other values in the other timesection but I found it very rudimentary method and I believe there should be other ways that are smarter, more efficient, and less time consuming.

[Adam Danz]

> [T1;T2] is not working and retrns the following error: All tables in the bracketed expression must have the same number of rows.

This is fishy. The example below shows that a vertical concatenation is perfectly fine when the tables have a different number of rows.

Please share

1. the result of head(T) for each table
2. the line of code where you're doing the concatenation
3. the entire error message.

Demo:

T1 = array2timetable((1:3)'.*ones(1,4), 'RowTimes', datetime('today')+(0:2))

T1 = 3x4 timetable
       Time        Var1    Var2    Var3    Var4
    ___________    ____    ____    ____    ____

    29-Jan-2021     1       1       1       1  
    30-Jan-2021     2       2       2       2  
    31-Jan-2021     3       3       3       3  

T2 = array2timetable((1:5)'.*ones(1,4), 'RowTimes', datetime('today')+(0:4))

T2 = 5x4 timetable
       Time        Var1    Var2    Var3    Var4
    ___________    ____    ____    ____    ____

    29-Jan-2021     1       1       1       1  
    30-Jan-2021     2       2       2       2  
    31-Jan-2021     3       3       3       3  
    01-Feb-2021     4       4       4       4  
    02-Feb-2021     5       5       5       5  

T = [T1; T2]

T = 8x4 timetable
       Time        Var1    Var2    Var3    Var4
    ___________    ____    ____    ____    ____

    29-Jan-2021     1       1       1       1  
    30-Jan-2021     2       2       2       2  
    31-Jan-2021     3       3       3       3  
    29-Jan-2021     1       1       1       1  
    30-Jan-2021     2       2       2       2  
    31-Jan-2021     3       3       3       3  
    01-Feb-2021     4       4       4       4  
    02-Feb-2021     5       5       5       5  

[Wolfgang McCormack]

@Adam Danz Hi, could you please post this to the answer so that I can mark it as the answer?

[Adam Danz]

Done. Thanks, Wolfgang.

Answer 1

[Adam Danz]

> [T1;T2] is not working and retrns the following error: All tables in the bracketed expression must have the same number of rows.

This is fishy. The example below shows that a vertical concatenation is perfectly fine when the tables have a different number of rows.

Please share

1. the result of head(T) for each table
2. the line of code where you're doing the concatenation
3. the entire error message.

Demo:

T1 = array2timetable((1:3)'.*ones(1,4), 'RowTimes', datetime('today')+(0:2))

T1 = 3x4 timetable
       Time        Var1    Var2    Var3    Var4
    ___________    ____    ____    ____    ____

    10-Mar-2021     1       1       1       1  
    11-Mar-2021     2       2       2       2  
    12-Mar-2021     3       3       3       3  

T2 = array2timetable((1:5)'.*ones(1,4), 'RowTimes', datetime('today')+(0:4))

T2 = 5x4 timetable
       Time        Var1    Var2    Var3    Var4
    ___________    ____    ____    ____    ____

    10-Mar-2021     1       1       1       1  
    11-Mar-2021     2       2       2       2  
    12-Mar-2021     3       3       3       3  
    13-Mar-2021     4       4       4       4  
    14-Mar-2021     5       5       5       5  

T = [T1; T2]

T = 8x4 timetable
       Time        Var1    Var2    Var3    Var4
    ___________    ____    ____    ____    ____

    10-Mar-2021     1       1       1       1  
    11-Mar-2021     2       2       2       2  
    12-Mar-2021     3       3       3       3  
    10-Mar-2021     1       1       1       1  
    11-Mar-2021     2       2       2       2  
    12-Mar-2021     3       3       3       3  
    13-Mar-2021     4       4       4       4  
    14-Mar-2021     5       5       5       5  

[Wolfgang McCormack]

@Adam Danz thank you, Adam!