Combine date and duration into single datetime column

Hello!

I have a vector containing the data in a datetime format (MM/dd/uuuu)and the vector containing the hours of the days in duration format(hh:mm:ss)

I want to combine the two vectors in order to get a single datetime vector having date and hour togheter.

I tried this code but it seems that is not working:

new_datetime=date+hour;

Answer 1

[Star Strider]

Add them —

DT = datetime(repmat([2018 01 01], 5, 1))

DT = 5×1 datetime array
   01-Jan-2018
   01-Jan-2018
   01-Jan-2018
   01-Jan-2018
   01-Jan-2018

DU = duration('00:00:00') + 5*minutes(0:4)'

DU = 5×1 duration array
   00:00:00
   00:05:00
   00:10:00
   00:15:00
   00:20:00

Combined = DT + DU

Combined = 5×1 datetime array
   01-Jan-2018 00:00:00
   01-Jan-2018 00:05:00
   01-Jan-2018 00:10:00
   01-Jan-2018 00:15:00
   01-Jan-2018 00:20:00

.

[Enrico Gambini]

I tried. Your code works.

But this approach it is not working with my own data and I don't know why.

Got a 420002x1 datetime array and a 420002x1 duration array. I add them and it remains only the date not followed by the hours

[Star Strider]

Please attach a sample of your data, preferably as a text file, since it is difficult to work with .mat files with the online Run feature here.

DT = datetime(repmat([2018 01 01], 5, 1))

DT = 5×1 datetime array
   01-Jan-2018
   01-Jan-2018
   01-Jan-2018
   01-Jan-2018
   01-Jan-2018

DU = duration('00:00:00') + 5*minutes(0:4)'

DU = 5×1 duration array
   00:00:00
   00:05:00
   00:10:00
   00:15:00
   00:20:00

T1 = table(DT,DU, 'VariableNames',{'date','hour'})

T1 = 5×2 table
       date          hour  
    ___________    ________

    01-Jan-2018    00:00:00
    01-Jan-2018    00:05:00
    01-Jan-2018    00:10:00
    01-Jan-2018    00:15:00
    01-Jan-2018    00:20:00

T1.Combined = T1{:,1} + T1{:,2}                             % Cell Reference

T1 = 5×3 table
       date          hour            Combined      
    ___________    ________    ____________________

    01-Jan-2018    00:00:00    01-Jan-2018 00:00:00
    01-Jan-2018    00:05:00    01-Jan-2018 00:05:00
    01-Jan-2018    00:10:00    01-Jan-2018 00:10:00
    01-Jan-2018    00:15:00    01-Jan-2018 00:15:00
    01-Jan-2018    00:20:00    01-Jan-2018 00:20:00

T1 = T1(:,1:2)

T1 = 5×2 table
       date          hour  
    ___________    ________

    01-Jan-2018    00:00:00
    01-Jan-2018    00:05:00
    01-Jan-2018    00:10:00
    01-Jan-2018    00:15:00
    01-Jan-2018    00:20:00

T1.Combined = T1.date + T1.hour                             % Variable Name Reference

T1 = 5×3 table
       date          hour            Combined      
    ___________    ________    ____________________

    01-Jan-2018    00:00:00    01-Jan-2018 00:00:00
    01-Jan-2018    00:05:00    01-Jan-2018 00:05:00
    01-Jan-2018    00:10:00    01-Jan-2018 00:10:00
    01-Jan-2018    00:15:00    01-Jan-2018 00:15:00
    01-Jan-2018    00:20:00    01-Jan-2018 00:20:00

I am not certain how you are combining them as table variables, so considering that could be the problem, I offer these examples that both lead to a correct result.

.

[Enrico Gambini]

Yes, thank you. I'll attach the txt file.

I would like to merge "date" and "hour" columns.

Thank you very much

[Stephen23]

T = readtable('T.txt')

Warning: Column headers from the file were modified to make them valid MATLAB identifiers before creating variable names for the table. The original column headers are saved in the VariableDescriptions property.
Set 'VariableNamingRule' to 'preserve' to use the original column headers as table variable names.

T = 200000×1 table
         dateHour      
    ___________________

    01/01/2018 00:00:00
    01/01/2018 00:05:00
    01/01/2018 00:10:00
    01/01/2018 00:15:00
    01/01/2018 00:20:00
    01/01/2018 00:25:00
    01/01/2018 00:30:00
    01/01/2018 00:35:00
    01/01/2018 00:40:00
    01/01/2018 00:45:00
    01/01/2018 00:50:00
    01/01/2018 00:55:00
    01/01/2018 01:00:00
    01/01/2018 01:05:00
    01/01/2018 01:10:00
    01/01/2018 01:15:00

[Enrico Gambini]

Idk what happened, try with this new attachement...

[Star Strider]

They appear to be merged in the file! (The ‘new attachment’ read here in the edited Comment.)

T1 = readtable('https://www.mathworks.com/matlabcentral/answers/uploaded_files/902050/T.txt', 'VariableNamingRule','preserve')

T1 = 200000×1 table
         date→hour     
    ___________________

    01/01/2018 00:00:00
    01/01/2018 00:05:00
    01/01/2018 00:10:00
    01/01/2018 00:15:00
    01/01/2018 00:20:00
    01/01/2018 00:25:00
    01/01/2018 00:30:00
    01/01/2018 00:35:00
    01/01/2018 00:40:00
    01/01/2018 00:45:00
    01/01/2018 00:50:00
    01/01/2018 00:55:00
    01/01/2018 01:00:00
    01/01/2018 01:05:00
    01/01/2018 01:10:00
    01/01/2018 01:15:00

What else is there to do?

.

[Enrico Gambini]

I really don't know how this is possible. I simply exported the two columns of the table and they have been automatically merged... hence, I will use this datetime in table "T" for my work.

Neverthless, your answer should have worked and I'm gonna accept it.

Thank you for your patience!

[Star Strider]

Thank you!

As always, my pleasure!