Datetime from Unix time miliseconds

Hello,

I am using a data source that gives a unix time(down to miliseconds), I want to convert this to a date string, I am currently using

dt = datestr(datetime(values(1)/1000, 'ConvertFrom', 'posixtime') + hours(2)); %add 2 hours for gmt +2

The division by 1000 is because the datestring can't handle mili second unix time.

With google I can't find a way to tell matlab to include milliseconds to datetime, but I really need the milliseconds. Did I overlook something?

Thanks in advance,

Bearpie

P.S. Matlab 2016A

[Bearpie]

I ended up removing the last 3 chars from the unix time in ms to get it in seconds. Than I parsed the last 3 to an int and added that to datetime by using

datetime + milliseconds(lastThreeChars);

This added the milliseconds to my datetime!

Answer 1

[Bearpie]

I ended up removing the last 3 chars from the unix time in ms to get it in seconds. Than I parsed the last 3 to an int and added that to datetime by using

datetime + milliseconds(lastThreeChars);

This added the milliseconds to my datetime!

Answer 2

[Peter Perkins]

It's not entirely clear to me what you're starting out with. "unix time" isiusually measure in seconds since 1970, you may have seconds with a fraction, or you may have seconds*1000 as an integer. I'm thinking the latter based on your code. You're also correcting for local time zone in your string.

>> unixmillis = 1470243132021
unixmillis =
             1470243132021
>> t = datetime(unixmillis/1000,'ConvertFrom','posixTime','TimeZone','America/New_York','Format','dd-MMM-yyyy HH:mm:ss.SSS')
t = 
   03-Aug-2016 12:52:12.021
>> char(t)
ans =
03-Aug-2016 12:52:12.021

Numerically, the division by 1000 isn't the greatest, but for many purposes (including, making a string), it's good enough. You could also do this:

>> datetime(1970,1,1,'Format','dd-MMM-yyyy HH:mm:ss.SSS') + milliseconds(unixmillis)
ans = 
   03-Aug-2016 16:52:12.021

Answer 3

[Guillaume]

Both datetime and datestr support milliseconds just fine. You just need to tell them you want the milliseconds displayed.

To force datestr to show milliseconds:

dt = datestr(yourdatetime, 'dd-mmm-yyyy HH:MM:SS:FFF'); %FFF is for millisecond

Once you've converted to datestring you've lost all the information not encoded in the string, so instead I would keep the information as datetime, and convert the datetime to a string as required

yourdatetime.Format = 'dd-MMM-yyyy HH:mm:ss SSS'); %note that datetime format syntax is not the same as datestr
c = char(yourdatetime)  %to get a string out of a datetime