Converting a string to a datetime array for the 29th February

When I enter the following code:

a = 'Feb 29 08:59:21';

t = datetime(a,'InputFormat','MMM dd HH:mm:ss');

I receive an error:

-------------------------------

Error using datetime (line 635)

Unable to convert 'Feb 29 08:59:21' to datetime using the format 'MMM dd HH:mm:ss'. If the date/time text contains day, month, or time zone names in a

language foreign to the 'en_US' locale, those might not be recognized. You can specify a different locale using the 'Locale' parameter.

-------------------------------

If I use:

a = 'Feb 28 08:59:21';

t = datetime(a,'InputFormat','MMM dd HH:mm:ss');

This works fine.

I assume this has something to do with there being no year specified and the 29th February only happening on a leap year?

Michael.

[Stephen23]

"I assume this has something to do with there being no year specified and the 29th February only happening on a leap year?"

Probably.

What year do you expect that datetime object to use, if you do not provide it with a year?

[Jiri Hajek]

Hint: try to remove the semicolon on your second line of your successully working code, to see the value.

t = datetime(a,'InputFormat','MMM dd HH:mm:ss')

You will see that MATLAB implicitly assumes the date is within the current year.

[Michael Daly]

I see your point thanks.

[Peter Perkins]

Michael, the error msg you got is correct, but not all that helpful. We are definitely aware of that, and it will improve at some point.

Also, notice that while

% datetime("29-Feb-2022")

is an error,

datetime(2022,2,29)

ans = datetime
   01-Mar-2022

is not. Why is that? Because you'd want

t = datetime(2022,2,1:60);
t([1 end])

ans = 1×2 datetime array
   01-Feb-2022   01-Apr-2022

to work. That has a legitimate use case. There's no legitimate use for "29-Feb-2022", no software should ever be creating that timestamp for import into MATLAB.

[Michael Daly]

Interesting point here too. Some things are relative.

Answer 1

[Dongyue]

If you do not specify the year, MATLAB will automatically view it as the current year. Since 2022 is not a leap year, you will get an error if you want to use datetime for Feb 29th.