Change the format of all Datetime variables in a Table

Is there any way to change the format of all the datetime variables in a table?

Var1 = datetime({'2015-12-18 08:03:05';'2015-12-18 10:03:17'});
Var2 = [20; 90]
Var3 = datetime({'2016-12-18 00:03:00';'2017-12-28 12:11:00'});
T = table(Var1, Var2, Var3);

S = vartype('datetime')
T{:,S}.Format = 'dd/MM/yyyy' %This does not work

What I would like to achieve is the result obtained from the following:

T.Var1.Format = 'dd/MM/yyyy'
T.Var3.Format = 'dd/MM/yyyy'

The thing though is that I am looping over different tables T, and at some iterations either (or both) Var1 and Var3 can be empty. Therefore, doing the latter method (i.e. setting the format of each variable individually) returns an error: Unable to perform assignment because dot indexing is not supported for variables of this type. Also, I have a lot more variables, so I would like to avoid if-isempty()-statements. Hence, I was wondering if there is a way to change the format of a few selected variables (-datetimes-) at once.

Answer 1

[Walter Roberson]

T = convertvars(T, @isdatetime, @(t) datetime(t, 'Format', 'dd/MM/yyyy'))

I tested to confirm that passing a datetime object as the parameter to datetime() can be used to construct new objects with different properties.

[Star Strider]

Walter — Are you referring to the convertvars function?

[Haris K.]

Yes, this is what Walter meant.

T = convertvars(T, @isdatetime, @(t) datetime(t, 'Format', 'dd/MM/yyyy'))

That works well. I am actually using Walter's solution, but here's an alternative solution:

datetime.setDefaultFormats('default','dd/MM/yyyy')

Thank you all.

[Gabor]

Undefined function 'convertvars' for input arguments of type 'datetime'.

[Stephen23]

@Gabor: CONVERTVARS was introduced in R2018b. Are you using an earlier version?