Dear, This is a very efficient way. I have checked some values and it is what is was looking for.
I want to find the days called dry-weather days. It depends but in my case it is a dry day if on this day the precipitation "N" is equal or less than 0.3 mm and if on the day before the day with N <= 0.3 mm the precipitation is also equal or less than 0.3 mm. With this you can set a periods of rainy and dry weather. I didn't have time check to other methods but soon I will. Next I want to take the entire time series from 2010-01-01 unti 2013-12-31. With your reply I will have two vectors then which I need to combine to find group into rainy day or dry weather day. I think I am going to us merge() to put the subset vector back into a original data.frame with all dates. At first I want to find the solution by myself. If it won't work I will post a new question to R-help. Thanks a lot. Christoph 2014-04-28 14:27 GMT+02:00 Frede Aakmann Tøgersen <fr...@vestas.com>: > Hi > > Here is a very simple way. > > > mydat <- read.table(text=" > Date N > 2010-01-01 0 > 2010-01-02 1.9 > 2010-01-03 0 > 2010-01-04 0 > 2010-01-05 1.6 > 2010-01-06 0 > 2010-01-07 0.3 > 2010-01-08 0 > 2010-01-09 1.1 > 2010-01-10 1.7 > 2010-01-11 2.6 > 2010-01-12 0 > 2010-01-13 0 > 2010-01-14 0 > 2010-01-15 0 > 2010-01-16 0 > 2010-01-17 0 > 2010-01-18 0.2 > 2010-01-19 0 > 2010-01-20 0 > 2010-01-21 0 > 2010-01-22 0 > 2010-01-23 0 > 2010-01-24 0 > 2010-01-25 0 > 2010-01-26 0 > 2010-01-27 1.9 > 2010-01-28 6.2 > 2010-01-29 0 > 2010-01-30 0", sep = "", h = TRUE) > > mydat$NdayBefore <- c(NA, mydat[-nrow(mydat), "N"]) > > head(mydat) > > subset(mydat, N <= 0.3) > > subset(mydat, N <= 0.3 & NdayBefore <= 0.3) > > Yours sincerely / Med venlig hilsen > > > Frede Aakmann Tøgersen > Specialist, M.Sc., Ph.D. > Plant Performance & Modeling > > Technology & Service Solutions > T +45 9730 5135 > M +45 2547 6050 > fr...@vestas.com > http://www.vestas.com > > Company reg. name: Vestas Wind Systems A/S > This e-mail is subject to our e-mail disclaimer statement. > Please refer to www.vestas.com/legal/notice > If you have received this e-mail in error please contact the sender. > > > > -----Original Message----- > > From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] > > On Behalf Of Christoph Schlächter > > Sent: 28. april 2014 10:38 > > To: r-help@r-project.org > > Subject: [R] subset of obersevation depending on multiple conditions > > > > Hello, > > > > I want to subset a data.frame containing the variables "Date" in (%Y %m > %d > > ) and "N". > > > > I want to print "Date" and "N" if N is less than or equal to 0.3 and if > > "N" is also less than or equal to 0.3 on the day before the day where "N" > > is less than or equal to 0.3. > > > > This would be the case in line 3 and 4 , 6 and 7, 12 to 18, and so on. > > > > "Date" "N" > > "1" 2010-01-01 0 > > "2" 2010-01-02 1.9 > > "3" 2010-01-03 0 > > "4" 2010-01-04 0 > > "5" 2010-01-05 1.6 > > "6" 2010-01-06 0 > > "7" 2010-01-07 0.3 > > "8" 2010-01-08 0 > > "9" 2010-01-09 1.1 > > "10" 2010-01-10 1.7 > > "11" 2010-01-11 2.6 > > "12" 2010-01-12 0 > > "13" 2010-01-13 0 > > "14" 2010-01-14 0 > > "15" 2010-01-15 0 > > "16" 2010-01-16 0 > > "17" 2010-01-17 0 > > "18" 2010-01-18 0.2 > > "19" 2010-01-19 0 > > "20" 2010-01-20 0 > > "21" 2010-01-21 0 > > "22" 2010-01-22 0 > > "23" 2010-01-23 0 > > "24" 2010-01-24 0 > > "25" 2010-01-25 0 > > "26" 2010-01-26 0 > > "27" 2010-01-27 1.9 > > "28" 2010-01-28 6.2 > > "29" 2010-01-29 0 > > "30" 2010-01-30 0 > > > > I tried some methods with subset but I couldn't work it out. Maybe I have > > to use something like " for (i in x) {} but as a beginner I really don't > > know how to do it. > > > > Can somebody please help me with this. > > > > Thanks in advance, > > > > Christoph > > > > [[alternative HTML version deleted]] > > > > ______________________________________________ > > R-help@r-project.org mailing list > > https://stat.ethz.ch/mailman/listinfo/r-help > > PLEASE do read the posting guide http://www.R-project.org/posting- > > guide.html > > and provide commented, minimal, self-contained, reproducible code. > [[alternative HTML version deleted]]
______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
