Create a timetable for every minute in one day

Is it possible to generate a timetable where each row represents one minute throughout the day? A table with a height of 1440 with each row increasing by 1 minute, starting at 00:00:00?

I initially tried it with duration but then realised that duration and timestamps are not the same.

j = 0;
for i = 1:24

    T_Daily = duration(j,0:59,0); 

    All_T_Daily{i} = T_Daily;

    j=j+1;
end

T_Daily= horzcat(All_T_Daily{:});
T_Daily = T_Daily.';

Answer 1

[Scott MacKenzie]

Here you go. As seen in the output from whos, there are 1441 rows in the timetable, one for each minute in the day plus the first minute in the next day.

% create datetime array for Aug 1, 2021 with 1 row per minute
DT = datetime(2021,8,1):minutes(1):datetime(2021,8,2);

% covert to table and add some test data
T1 = array2table(DT');
T1.Data = rand(height(T1),1);

% convert to timetable
TT1 = table2timetable(T1);
whos

  Name         Size              Bytes  Class        Attributes

  DT           1x1441            11528  datetime               
  T1        1441x2               24255  table                  
  TT1       1441x1               24041  timetable              

[Mark Maders]

Can this be done without giving a date? Just focused on the time

[Scott MacKenzie]

Oops, I jumped the gun on this one. Seems duration is probably not a good choice. See @Star Strider's answer and @Peter Perkins comments.

I still think the timetable arrangement with a datetime column is reasonable, since it gives you one-minute increments throughout the day.

Answer 2

[Star Strider]

Without a date, it creates a duration array, not a datetime array. The two are different, especially with respect to 'Format' options and other properties.

One possibility:

TT1 = table((0:minutes(1):hours(24)).')

TT1 = 1441×1 table
     Var1 
    ______

     0 min
     1 min
     2 min
     3 min
     4 min
     5 min
     6 min
     7 min
     8 min
     9 min
    10 min
    11 min
    12 min
    13 min
    14 min
    15 min

TT1.Var1.Format = 'hh:mm:ss'

TT1 = 1441×1 table
      Var1  
    ________

    00:00:00
    00:01:00
    00:02:00
    00:03:00
    00:04:00
    00:05:00
    00:06:00
    00:07:00
    00:08:00
    00:09:00
    00:10:00
    00:11:00
    00:12:00
    00:13:00
    00:14:00
    00:15:00

Noon = TT1.Var1(719:722)

Q1 = 4×1 duration array
   11:58:00
   11:59:00
   12:00:00
   12:01:00

Using the dateshift funciton is also a possibility for a datetime array.

.

[Mark Maders]

It might help to explain why I would like to do this. I have a table containing various electric vehicles. This has a datetime of arrival, a datetime of departure, and a charging requirement for each vehicle. Say the charging rate is 200kW for one vehicle, I want to fill the column next to the time with 200. So say the vehicle arrives at 12:00:00 and departs at 12:30:00 for example, the table would look like:

time power(kW)

11:59:00 0

12:00:00 200

12:00:01 200

...

12:29:00 200

12:30:00 0

The date will of course vary from day to day, so I want the table to be flexible and accept any date, but record the data against time. I can then display this graphically for the day

[Star Strider]

Simply changing the 'Format' could do what you want, displaying only the times.

For plotting, see the documentation section on Plot Dates and Durations for a detailled description.

.

[Peter Perkins]

As SS says, datetime is for specific points in time, duration is for elapsed time. You can absolutely use duration as a time of day, but it does not roll over at 24:00:00. So if you are adding thigs to a "time of day" duration, you may need to handle roll over. But of course you will also have to increment the date. Which leads to back to using datetime, probably.