[R] bug in as.POSIXct ?

Jason Turner jasont at indigoindustrial.co.nz
Thu Dec 4 21:04:55 CET 2003


apjaworski at mmm.com wrote:
> My particular problem was much simpler.  I had a bunch of data from a data
> acquisition system with sampling interval of 1 minute.  The system used a
> simple compression scheme, where a data point was reported only when the
> change in response was sufficiently large.  For example, a fragment like
> this
> 
>       Oct. 26 0:01:00       y1
>       Oct. 26 0:05:00       y2
> 
> means that the values for 0:02, 0:03 0:04 where essentially y1.
> 
> I needed to "decompress" the data set, i.e., fill in the gaps, so I was
> checking for differences of 1 minute and that is when I discovered the
> "error".

I presume the data acq. system doesn't know about time zone changes? In 
cases like this, I specify the time zone as UTC for all analysis, and 
convert it back to my time zone for reporting.  If it does know time 
zones, you have to force the CST/CDT zone.  Import, convert to text, 
paste the appropriate string, convert to POSIXct.

Who wants the world to switch to "metric time"?  (raises hand). :)

Cheers

Jason


-- 
Indigo Industrial Controls Ltd.
http://www.indigoindustrial.co.nz
64-21-343-545
jasont at indigoindustrial.co.nz




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