how to convert 18 digits timestamp to readable date and time in MATLAB

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ameen
ameen 2015-4-23
回答： William Bertram 2017-3-8
I have data with a time step consists of 18 digits such as 634019142119225390. This date should be in February 2010 by the way.
How can i convert this into readable date and time in MATLAB ?
Unfortunately i don't know what is the format of this timestamp. Is it UNIX or Julian or what.
Many Thanks in advance
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Guillaume
Guillaume 2015-4-24
I'm not sure why you're providing more samples. As far as I can tell, I've answered your question.

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Guillaume
Guillaume 2015-4-23
编辑：James Tursa 2015-4-24
This page may be useful.
Most likely, your timestamp is a .Net System.DateTime
>>ts = int64(634019142119225390);
>>dt = System.DateTime(ts); %Note that you need to be on Windows for this to work
>>dt.ToString
ans =
16/02/2010 00:00:00
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Guillaume
Guillaume 2015-4-24
As per the documentation of System.DateTime, its resolution is 100 nanoseconds. Therefore the difference between your two timestamps is only 1 microsecond.
You need to add 10,000,000 (1e7) to just go up one second.

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Peter Perkins
Peter Perkins 2015-4-24
Another option, if you have MATLAB R2014b or later, is this:
>> x = [uint64(634019142119225390) uint64(634019142129597610) uint64(634019142139821660)]
x =
634019142119225390 634019142129597610 634019142139821660
>> datetime(double(x)/1e7,'ConvertFrom','epochtime','Epoch','1-Jan-0001','Format','dd-MMM-yyyy HH:mm:ss.SSSSSSSSS')
ans =
16-Feb-2010 10:50:11.922531250 16-Feb-2010 10:50:12.959757812 16-Feb-2010 10:50:13.982171875
But that's not exactly right -- those uint64's are larger than flintmax, so casting them to double introduces round-off. You may not care about 100ns resolution. If you only cared about 1ms resolution, you could do this:
>> datetime(double(x/1e4)/1e3,'ConvertFrom','epochtime','Epoch','1-Jan-0001','Format','dd-MMM-yyyy HH:mm:ss.SSS')
ans =
16-Feb-2010 10:50:11.923 16-Feb-2010 10:50:12.960 16-Feb-2010 10:50:13.982
But to get exactly what you started with, do this:
>> secs = (x-.5e7)/1e7
secs =
63401914211 63401914212 63401914213
>> milliSecs = double(x - uint64(secs)*1e7)/1e4
milliSecs =
922.539 959.761 982.166
>> datetime(secs,'ConvertFrom','epochtime','Epoch','1-Jan-0001','Format','dd-MMM-yyyy HH:mm:ss.SSSSSSSSS') + milliseconds(milliSecs)
ans =
16-Feb-2010 10:50:11.922539000 16-Feb-2010 10:50:12.959761000 16-Feb-2010 10:50:13.982166000
William Bertram
William Bertram 2017-3-8
634019142119225390 appears to be the number of nanoseconds that has elapsed since 01/01/0001 00:00. Here is a quick Powershell to convert that to human readable:
$timestamp = 636244407153688066 / 10000000
$epochDate = [datetime]"01/01/0001 00:00"
$epochDate.AddSeconds($timestamp)

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