On Nov 20, 2009, at 6:26 AM, Stefan Strohmeier wrote:
Dear R users,
I have a time series of precipitation data. The time series
comprises ~ 20 years and it is supposed to be constant (one value
per day), but due to some failure of the measuring device some days
or periods are missing. I would like to find these missing days or
periods just to get a first idea about the reliability of the
measurements. The only function I could find was is.constant(), but
of course I only get a true or false statement instead of the dates
missing.
Google searches and a look at the R help mailing did not reveal an
answer.
Please find attached a few dates of the time series with missing
values from February to April. I would like R to detect those
missing dates.
> dtdta <- read.table(textConnection("2916 2002-02-17 0.0
+ 2917 2002-02-18 0.3
+ 2918 2002-02-19 3.8
+ 2919 2002-02-20 43.6
+ 2920 2002-02-21 1.0
+ 2921 2002-02-22 5.6
+ 2922 2002-02-23 10.6
+ 2923 2002-02-24 2.8
+ 2924 2002-02-25 19.1
+ 2925 2002-02-26 20.5
+ 2926 2002-03-06 0.0
+ 2927 2002-05-06 0.0
+ 2928 2002-05-07 0.0
+ 2929 2002-05-08 0.0
+ 2930 2002-05-09 0.0") )
> dtdta[dtdta$V3 == 0, ]
V1 V2 V3
1 2916 2002-02-17 0
11 2926 2002-03-06 0
12 2927 2002-05-06 0
13 2928 2002-05-07 0
14 2929 2002-05-08 0
15 2930 2002-05-09 0
You seem to be using "0" as a missing marker. That's bad practice, but
I suppose it's possble you cannot change how your instruments report.
You should be using NA and the functions that support proper treatment
of "missingness".
--
David
Any hints or solutions are highly appreciated.
Regards,
Stefan Strohmeier
2916 2002-02-17 0.0
2917 2002-02-18 0.3
2918 2002-02-19 3.8
2919 2002-02-20 43.6
2920 2002-02-21 1.0
2921 2002-02-22 5.6
2922 2002-02-23 10.6
2923 2002-02-24 2.8
2924 2002-02-25 19.1
2925 2002-02-26 20.5
2926 2002-03-06 0.0
2927 2002-05-06 0.0
2928 2002-05-07 0.0
2929 2002-05-08 0.0
2930 2002-05-09 0.0
______________________________________________
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
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David Winsemius, MD
Heritage Laboratories
West Hartford, CT
______________________________________________
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
