UTC time

How to convert UTC time to time in YEAR MONTH DAY HH MM SS?

UTC is 1263403529

I need

 13-Jan-2012 17:25:29

Answer 1

[C.J. Harris]

Grab the following file from the File Exchange:

http://www.mathworks.com/matlabcentral/fileexchange/7244

Then call:

x = 1263403529;
y = datestr(utc2datenum(x));

[Jisha]

I get an error:

Attempt to execute SCRIPT utc2datenum as a function:

[C.J. Harris]

Ensure you have the 'utc2datenum.mexw32' file in the same location as 'utc2datenum.m'.

[Jisha]

I do and the entire folder is on the MATLAB path.. it still gives me this error.. I have MATLAB 64 bit R2012a

[C.J. Harris]

Then that's your problem. MATLAB isn't recognising the '.mexw32' file since you are using a 64-bit version of MATLAB. You will have to recompile the source code in order to run it on your system.

[Jisha]

Thanks..

[Christoph Kessler]

What is the use if Answer requires a specific environment like 64 or 32-bit. Can you simply change without source code?

Answer 2

[Steven Lord]

You can do this using datetime.

>> dt = datetime(1263403529, 'ConvertFrom', 'posixtime')

dt = 

    datetime

     13-Jan-2010 17:25:29

Answer 3

[James Tursa]

If this is "seconds since 1970-01-01 00:00:00 TAI" it is more properly called "unix time" or "posix time" or sometimes "epoch time", not UTC. E.g., see this article:

http://en.wikipedia.org/wiki/Unix_time

If that is the case you can simply calculate your result as:

x = 1263403529;
e = datenum('01-jan-1970 00:00:00');
y = datestr(e+x/86400,'dd-mm-yyyy hh:mm:ss');

[C.J. Harris]

For the format '13-Jan-2012 17:25:29' the last line would have to be:

y = datestr(e+x/86400,'dd-mmm-yyyy HH:MM:SS');

[James Tursa]

Oops. Thanks.

[Geoff]

It's best to avoid string processing where it's not necessary:

e = datenum(1970,1,1,0,0,0);

[James Tursa]

Well, I would assume e would be a one-time only calculation in which case the string is more readable IMO. But if the goal is to make this calculation faster then I would simply eliminate it altogether. E.g.,

y = datestr(719529+x/86400,'dd-mmm-yyyy HH:MM:SS');

along with a comment stating where the magic number 719529 comes from.

Answer 4

[Uilke Stelwagen]

Wrote my own utc2datenum and discovered that 'UTC' 1263403529 is NOT "13-Jan-2012 17:25:29" but 1326475529 is. I.e. datestr(utc2datenum(1263403529)) = 13-Jan-2010 17:25:29, hence differing 2 years, while datestr(utc2datenum(1326475529)) = 13-Jan-2012 17:25:29. Best thing is to check a routine or algorithm with the 'UTC' time example given on http://en.wikipedia.org/wiki/Unix_time instead of starting with a wrong example.

[Dan]

Current Wikipedia time is

1344541161 (2012-08-09 19:39:21Z)

>> utc = 1344541161

utc =

     1.3445e+09

>> datestr(datenum([1970, 1, 1, 0, 0, utc]))

ans =

09-Aug-2012 19:39:21

I just blew everyone's mind...

[marleen_ade]

perfect! Leave out the square brackets, and it works here too (R2015a 32 bit)