MATLAB: Duration in double between two datenum

Question

I have two dates given in text format, I want to have the real duration in seconds between the two values.

The answer is -24, and I can do it parsing the strings. But does MATLAB have a function to do it nice and quick?

If I do the following the answer is not a -24 that I can use as a double:

    datenum('2018-09-07 18:36:05.079')-datenum('2018-09-07 18:36:29.079')

I need this time for a Simulink simulation. For example, I might need the duration in seconds between two days.

Answer 1

To get seconds simply multiply the days by 60*60*24:

>> F = 'yyyy-mm-dd HH:MM:SS.FFF';
>> D =  datenum('2018-09-07 18:36:05.079',F)-datenum('2018-09-07 18:36:29.079',F);
>> D*60*60*24
ans = -24.000