Hi, If I understand your question, this would do it: z2<-transform(z2,Hr=format(index(z2),"%H")) z2 # Ta HR RS v Hr #2010-01-01 11:00:00 5.51 100 0 1.1 11 #2010-01-02 11:00:00 5.64 100 0 2.4 11 #2010-01-03 06:00:00 5.40 100 0 2.3 06 A.K.
----- Original Message ----- From: Dominic Roye <dominic.r...@gmail.com> To: arun <smartpink...@yahoo.com> Cc: Sent: Saturday, November 24, 2012 6:36 AM Subject: Re: [R] daily maximum temperature Hello, Your first option works well, but how i can get also the hour of the daily maximum temperature? Thanks! 2012/11/23 arun <smartpink...@yahoo.com>: > > > Hi, > Since you mentioned filtering the daily maximum temperature, this may help: > datos<-read.table(text=" > X, Ta, HR, RS, v > 1/1/2010 1:00:00,5.28,100,0,2.3 > 1/1/2010 6:00:00,5.45,100,0,2.5 > 1/1/2010 11:00:00,5.51,100,0,1.1 > 2/1/2010 1:00:00,5.33,100,0,2.1 > 2/1/2010 6:00:00,5.48,100,0,2.3 > 2/1/2010 11:00:00,5.64,100,0,2.4 > 3/1/2010 1:00:00,5.12,100,0,2.0 > 3/1/2010 6:00:00,5.40,100,0,2.3 > 3/1/2010 11:00:00,5.32,100,0,1.7 > ",sep=",",header=TRUE,stringsAsFactors=FALSE) > library(zoo) > z<-zoo(datos[,-1],order.by=as.POSIXct(datos[,1],format="%d/%m/%Y %H:%M:%S")) > > aggregate(z$Ta,by=list(as.Date(index(z))),max) #gives the daily maximum >temperatures > #2010-01-01 2010-01-02 2010-01-03 > # 5.51 5.64 5.40 > > > For filtering the data: > > > flag<-unlist(lapply(split(z,as.Date(index(z))),function(x) > data.frame(x[,1]==max(x[,1]))),use.names=F) > z1<-transform(z,flag=flag) > z2<-z1[,1:4][z1$flag==1,] #filtered the maximum daily temp data > z2 > # Ta HR RS v > #2010-01-01 11:00:00 5.51 100 0 1.1 > #2010-01-02 11:00:00 5.64 100 0 2.4 > #2010-01-03 06:00:00 5.40 100 0 2.3 > > str(z2) > #‘zoo’ series from 2010-01-01 11:00:00 to 2010-01-03 06:00:00 > # Data: num [1:3, 1:4] 5.51 5.64 5.4 100 100 100 0 0 0 1.1 ... > #- attr(*, "dimnames")=List of 2 > #..$ : NULL > #..$ : chr [1:4] "Ta" "HR" "RS" "v" > #Index: POSIXct[1:3], format: "2010-01-01 11:00:00" "2010-01-02 11:00:00" >... > > #or > z3<-z > z3$Max<-ave(z[,1],as.Date(index(z)),FUN=max) > z4<-z3[,-5][z3$Ta==z3$Max,] > z4 > # Ta HR RS v > #2010-01-01 11:00:00 5.51 100 0 1.1 > #2010-01-02 11:00:00 5.64 100 0 2.4 > #2010-01-03 06:00:00 5.40 100 0 2.3 > > Hope it helps > > A.K. > > > > ----- Original Message ----- > From: Dominic Roye <dominic.r...@gmail.com> > To: r-help@r-project.org > Cc: > Sent: Friday, November 23, 2012 1:04 PM > Subject: [R] daily maximum temperature > > Hello, > > I want to filter the daily maximum temperature. For this i made this > skript, but it come out wrong results. Can anybody help me? > > Thanks for your help! > > Best regards > > > datos$X <- as.POSIXct(strptime(datos$X, "%d/%m/%Y %H:%M:%S")) > z <- aggregate(zoo(datos$Ta), as.POSIXct(datos$X), max) > > >> str(datos) > 'data.frame': 17137 obs. of 5 variables: > $ X : Factor w/ 17136 levels "00/01/1900 0:00:00",..: 2 3 4 5 6 7 8 9 10 11 > ... > $ Ta: num 5.28 5.45 5.54 5.54 5.51 5.51 5.5 5.56 5.58 5.63 ... > $ HR: int 100 100 100 100 100 100 100 100 100 100 ... > $ RS: int 0 0 0 0 0 0 0 0 0 0 ... > $ v : num 2.3 2.5 1.1 2.3 2.2 2.1 2.2 2.9 2.4 2.6 ... > > > > str(z) > ‘zoo’ series from 2010-01-01 00:10:00 to 2010-04-29 23:50:00 > Data: num [1:17129] 5.28 5.45 5.54 5.54 5.51 5.51 5.5 5.56 5.58 5.63 ... > Index: POSIXct[1:17129], format: "2010-01-01 00:10:00" "2010-01-01 > 00:20:00" "2010-01-01 00:30:00" "2010-01-01 00:40:00" ... >> > > ______________________________________________ > 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. > ______________________________________________ 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.
