A (simple) way to use ismember between datetime arrays with different formats

Is there a (simple) way to use ismember between datetime arrays with different formats?

In the following example, I want to find the dates that are present both in A and in B, regardless the time (i.e. hours, minutes, seconds):

% Input
A = datetime(...
   ['19-Jun-2023',
   '20-Jun-2023',
   '21-Jun-2023',
   '22-Jun-2023',
   '23-Jun-2023',
   '24-Jun-2023',
   '25-Jun-2023']);

tmp = [{'23-Jun-2023 19:00:00'}
    {'24-Jun-2023 16:00:00'}
    {'24-Jun-2023 11:00:00'}
    {'19-Jun-2023 16:00:00'}
    {'20-Jun-2023 10:00:00'}
    {'21-Jun-2023 10:00:00'}
    {'22-Jun-2023 09:00:00'}
    {'23-Jun-2023 14:00:00'}
    {'19-Jun-2023 17:00:00'}
    {'20-Jun-2023 11:00:00'}
    {'21-Jun-2023 17:00:00'}
    {'22-Jun-2023 15:00:00'}
    {'23-Jun-2023 06:00:00'}
    {'24-Jun-2023 11:00:00'}
    {'25-Jun-2023 19:00:00'}
    {'20-Jun-2023 11:00:00'}
    {'21-Jun-2023 09:00:00'}
    {'23-Jun-2023 12:00:00'}
    {'25-Jun-2023 17:00:00'}
    {'23-Jun-2023 12:00:00'}
    {'22-Jun-2023 07:00:00'}];
B = datetime(tmp, 'InputFormat', 'dd-MMM-yyyy HH:mm:ss');

ismember(A,B)

ans = 7x1 logical array
   0
   0
   0
   0
   0
   0
   0

[Stephen23]

The format is completely irrelevant. What matters is the date and time. If you want to ignore the time-of-day then use DATESHIFT before calling ISMEMBER.

[Sim]

Thanks a lot! I think I found that kind of solution at the same moment you wrote it :-)

I used:

dateshift(B, 'start', 'day');

Answer 1

[Benjamin Kraus]

I think the function you are looking for is dateshift.

A = datetime(...
   ['19-Jun-2023',
   '20-Jun-2023',
   '21-Jun-2023',
   '22-Jun-2023',
   '23-Jun-2023',
   '24-Jun-2023',
   '25-Jun-2023']);
tmp = [{'23-Jun-2023 19:00:00'}
    {'24-Jun-2023 16:00:00'}
    {'24-Jun-2023 11:00:00'}
    {'19-Jun-2023 16:00:00'}
    {'20-Jun-2023 10:00:00'}
    {'21-Jun-2023 10:00:00'}
    {'22-Jun-2023 09:00:00'}
    {'23-Jun-2023 14:00:00'}
    {'19-Jun-2023 17:00:00'}
    {'20-Jun-2023 11:00:00'}
    {'21-Jun-2023 17:00:00'}
    {'22-Jun-2023 15:00:00'}
    {'23-Jun-2023 06:00:00'}
    {'24-Jun-2023 11:00:00'}
    {'25-Jun-2023 19:00:00'}
    {'20-Jun-2023 11:00:00'}
    {'21-Jun-2023 09:00:00'}
    {'23-Jun-2023 12:00:00'}
    {'25-Jun-2023 17:00:00'}
    {'23-Jun-2023 12:00:00'}
    {'22-Jun-2023 07:00:00'}];
B = datetime(tmp, 'InputFormat', 'dd-MMM-yyyy HH:mm:ss');
ismember(A,dateshift(B,'start','day'))

ans = 7x1 logical array
   1
   1
   1
   1
   1
   1
   1

[Sim]

Thanks a lot @Benjamin Kraus! :-)

Answer 2

[Sim]

Maybe I found a way, but I am not sure about "dateshift(B, 'start', 'day')":

% Input
A = datetime(...
   ['19-Jun-2023',
   '20-Jun-2023',
   '21-Jun-2023',
   '22-Jun-2023',
   '23-Jun-2023',
   '24-Jun-2023',
   '25-Jun-2023']);

tmp = [{'23-Jun-2023 19:00:00'}
    {'24-Jun-2023 16:00:00'}
    {'24-Jun-2023 11:00:00'}
    {'19-Jun-2023 16:00:00'}
    {'20-Jun-2023 10:00:00'}
    {'21-Jun-2023 10:00:00'}
    {'22-Jun-2023 09:00:00'}
    {'23-Jun-2023 14:00:00'}
    {'19-Jun-2023 17:00:00'}
    {'20-Jun-2023 11:00:00'}
    {'21-Jun-2023 17:00:00'}
    {'22-Jun-2023 15:00:00'}
    {'23-Jun-2023 06:00:00'}
    {'24-Jun-2023 11:00:00'}
    {'25-Jun-2023 19:00:00'}
    {'20-Jun-2023 11:00:00'}
    {'21-Jun-2023 09:00:00'}
    {'23-Jun-2023 12:00:00'}
    {'25-Jun-2023 17:00:00'}
    {'23-Jun-2023 12:00:00'}
    {'22-Jun-2023 07:00:00'}];

% Solution
B = datetime(tmp, 'InputFormat', 'dd-MMM-yyyy HH:mm:ss','Format', 'dd-MMM-yyyy');
B2 = dateshift(B, 'start', 'day');
ismember(B2,A)

ans = 21x1 logical array
   1
   1
   1
   1
   1
   1
   1
   1
   1
   1
   1
   1
   1
   1
   1
   1
   1
   1
   1
   1
   1