how can I convert EST time to GMt time?

I have series of datevec (about 1000) in EST time zone that I would like to convert them to GMT, any help,

Thanks in advance,

Riyadh

Answer 1

[Meade]

Try using the 'TimeZone' property in the datetime function to re-interpret the input time in a new time zone.

See here: https://www.mathworks.com/help/matlab/matlab_prog/specify-time-zones.html

Best,

[Riyadh Muttaleb]

Thank you for your response, I have matrix of time (series) not one value

Answer 2

[Peter Perkins]

Unless you are using a version of MATLAB prior to R2014b, you probably should not be using datevecs. Convert them to datetimes.

>> dv = [2018,2,28,9,16,34; 2018,2,28,9,16,49;2018,2,28,9,17,04]
dv =
        2018           2          28           9          16          34
        2018           2          28           9          16          49
        2018           2          28           9          17           4
>> dt = datetime(dv,'TimeZone','America/New_York','Format','dd-MMM-uuuu HH:mm:ss z')
dt = 
  3×1 datetime array
   28-Feb-2018 09:16:34 EST
   28-Feb-2018 09:16:49 EST
   28-Feb-2018 09:17:04 EST
>> dt.TimeZone = 'UTC'
dt = 
  3×1 datetime array
   28-Feb-2018 14:16:34 UTC
   28-Feb-2018 14:16:49 UTC
   28-Feb-2018 14:17:04 UTC

[Meade]

That's a good tip! That looks like the best answer vs a messy loop of datestr calls.

Follow up Q:

Does datetime do lazy format parsing on the fly as well? One thing I like about datestr is that I can try to infer the format of the date if I don't know it a priori.

[Peter Perkins]

datetime does recognize some common formats. One of the problems with datenum/datestr/datevec was that they guess too much and sometimes get it wrong, silently.

Most common example is 01/02/2018. Because that's so common, datetime has some logic for that case based on your locale are and whether you also have, for example, 01/15/2018. So for me, in the US, it guesses month/day:

>> datetime('01/02/2018')
Warning: Successfully converted the text to datetime using the format 'MM/dd/uuuu', but the format is ambiguous and
could also be 'dd/MM/uuuu'. To create datetimes from text with a specific format call:

    datetime(textinput,'InputFormat',infmt)

> In guessFormat (line 66)
  In datetime (line 631) 
ans = 
  datetime
   02-Jan-2018

But this case is unambiguous:

>> datetime({'01/02/2018' '01/15/2018'})
ans = 
  1×2 datetime array
   02-Jan-2018   15-Jan-2018

[Meade]

Thanks for the extra detail, I'll keep datetime in mind as I revamp processes.

I work with lots of data downstream of a workflow that doesn't adhere rigorously to a single format (e.g. ISO-8601) and in turn, I'll (cautiously) take all the help I can get.