how to floor time for each hour?

Hi Experts,

I have this time format, and i want to have the time only for each hour. Could anyone please help with this?

'12-Dec-2021 09:09:04'

'12-Dec-2021 09:24:04'

'12-Dec-2021 09:39:04'

'12-Dec-2021 09:54:04'

Much appreciated

[KSSV]

What's your desired output?

[Lilya]

to have the data at each hour instead of having different time steps for each hour

Answer 1

[Star Strider]

Try this —

tv = {'12-Dec-2021 09:09:04'
     '12-Dec-2021 09:24:04'
     '12-Dec-2021 09:39:04'
     '12-Dec-2021 09:54:04'};

dtv = datetime(tv, 'Format','dd-MMM-yyyy HH')                   % Display Only The Hour

dtv = 4×1 datetime array
   12-Dec-2021 09
   12-Dec-2021 09
   12-Dec-2021 09
   12-Dec-2021 09

dtv = datetime(tv, 'Format','dd-MMM-yyyy HH:00:00')             % Display Hour, Set Rest To Zeros

dtv = 4×1 datetime array
   12-Dec-2021 09:00:00
   12-Dec-2021 09:00:00
   12-Dec-2021 09:00:00
   12-Dec-2021 09:00:00

The 'Format' name-value pair controls the display, so set it however you want it.

.

[Lilya]

Thank you very much that was very helpful!

[Star Strider]

As always, my pleasure!

EDIT — (16 Mar 2022 at 12:40)

To summarise the data for each hour, use the table2timetable function and then the retime function.

.

[Lilya]

Noted

Answer 2

[Steven Lord]

If you want to actually modify the data rather than just changing how the data is displayed you can use dateshift.

tv = {'12-Dec-2021 09:00:00', 
     '12-Dec-2021 09:09:04'
     '12-Dec-2021 09:24:04'
     '12-Dec-2021 09:39:04'
     '12-Dec-2021 09:54:04'};

dtv = datetime(tv)

dtv = 5×1 datetime array
   12-Dec-2021 09:00:00
   12-Dec-2021 09:09:04
   12-Dec-2021 09:24:04
   12-Dec-2021 09:39:04
   12-Dec-2021 09:54:04

dtv2 = dateshift(dtv, 'start', 'hour')

dtv2 = 5×1 datetime array
   12-Dec-2021 09:00:00
   12-Dec-2021 09:00:00
   12-Dec-2021 09:00:00
   12-Dec-2021 09:00:00
   12-Dec-2021 09:00:00

To check that the data has actually been changed:

dtv2 == dtv(1)

ans = 5×1 logical array
   1
   1
   1
   1
   1

[Lilya]

Thank you for the help.. truly appreciated

[Steven Lord]

Based on your answer to KSSV's comment "to have the data at each hour instead of having different time steps for each hour" I suspect that storing your data in a timetable array and using retime to retime it to an hourly basis might be a solution to your larger problem.

[Lilya]

yes.. I did that and it works perfectly!

thank you very very much.

Answer 3

[Arif Hoq]

A={'12-Dec-2021 09:09:04'
    '12-Dec-2021 09:24:04'
    '12-Dec-2021 09:39:04'
    '12-Dec-2021 09:54:04'};
B=datetime(A,'Format','hh') % if only hour
B1=datetime(A,'Format','hh:mm:ss') % if hour,min,sec

[Lilya]

Thanks Arif.. appreciated