Best way to get date and time inputs from user and save as a datetime variable

My App Designer app allows the user to input a date and time range (start date, start time, end date, end time). I have 2 date pickers and two edit fields for the times (strings 'hhmm'). I save the 4 inputs as fields in a struct s. What is the cleanest way to incorporate the time inputs into the date variables? Or is there a better approach? The below works, but I feel there should be a slicker way.

       % construct the data subset timerange
        startDateTime = datetime(s.StartDate) + ...
            hours(str2double(s.StartTime(1:2))) + ...
            minutes(str2double(s.StartTime(3:4)));
        endDateTime = datetime(s.EndDate) + ...
            hours(str2double(s.EndTime(1:2))) + ...
            minutes(str2double(s.EndTime(3:4)));
        subsetPeriod = timerange(startDateTime,endDateTime,'closed');

Answer 1

[Stephen23]

No conversion back-and-forth is required: your approach of adding a DATETIME and DURATION object is the correct one. Sadly the DURATION creation has a very limited set of accepted formats, otherwise this really would be a trivial task :( So until TMW makes DURATION more flexible, we need workarounds. Here are three approaches:

HM = '2359'; % 'hhmm'
DT = datetime(2023,04,27)

DT = datetime
   27-Apr-2023

%Z0 = DT+duration(HM, 'InputFormat','hhmm') % what we want, but TMW won't allow.
Z1 = DT+duration([sscanf(HM,'%2d',[1,2]),0])

Z1 = datetime
   27-Apr-2023 23:59:00

Z2 = DT+duration(regexprep(HM,'(..)(..)','$1:$2'), 'InputFormat','hh:mm')

Z2 = datetime
   27-Apr-2023 23:59:00

Z3 = DT+duration([HM(1:2),':',HM(3:4)],  'InputFormat','hh:mm')

Z3 = datetime
   27-Apr-2023 23:59:00

Checking:

isequal(Z1,Z2,Z3)

ans = logical
   1

Answer 2

[Kevin Holly]

% construct the data subset timerange
startDateTime = datetime(s.StartDate + " " + s.StartTime, 'InputFormat', 'yyyy-MM-dd HHmm');
endDateTime = datetime(s.EndDate + " " + s.EndTime, 'InputFormat', 'yyyy-MM-dd HHmm');
subsetPeriod = timerange(startDateTime, endDateTime, 'closed');

[Rich006]

This doesn't work because the dates (s.StartDate and s.EndDate) are not strings. They are datetimes from the app datepicker.

[Kevin Holly]

In that case,

% convert datetime values to strings with format 'yyyy-MM-dd'
startDateStr = datestr(s.StartDate, 'yyyy-MM-dd');
endDateStr = datestr(s.EndDate, 'yyyy-MM-dd');

% construct the data subset timerange
startDateTime = datetime(startDateStr + " " + s.StartTime, 'InputFormat', 'yyyy-MM-dd HHmm');
endDateTime = datetime(endDateStr + " " + s.EndTime, 'InputFormat', 'yyyy-MM-dd HHmm');
subsetPeriod = timerange(startDateTime, endDateTime, 'closed');

Not sure if it better than what you have.

[Rich006]

OK, I was hoping for a neater way. It seems silly to convert back and forth. It would be nice if there was a "get time also" option in the date picker or some way to attach a time to the datepicker.