Ok, sorry, I thought the more complex details might be confusing and nobody might answer. Here is something which looks more like my real dataframe and also what I want to do with it:
That's my data frame: myframe <- data.frame (Timestamp=c("24.09.2012 09:00", "24.09.2012 10:00", "24.09.2012 11:00", "25.09.2012 09:00", "25.09.2012 10:00", "25.09.2012 11:00"), Hunger=c(1,1,2,5,1,6) , Longitude=c(8.91617, 8.92700, 8.92711, 8.92722, 8.92733, 8.92744), Latitude=c(54.5485, 54.5410, 54.5412, 54.5413, 54.5414, 54.5424) , AnimalID= c(rep("Ernie"))) head(myframe) myframestime <- as.POSIXct (strptime(as.character(myframe$Timestamp), "%d.%m.%Y %H:%M"), tz="GMT") myframe2 <- cbind (myframe,myframestime) myframe2$Timestamp <- NULL myframesxy <- project(cbind(myframe2$Longitude,myframe2$Latitude),"+proj=utm +zone=32 +ellps=WGS84") colnames(myframesxy) <- c("Long", "Lat") myframe3 <- cbind(myframe2, myframesxy) myframe3$Longitude <- NULL myframe3$Latitude <- NULL myframe3 And here is what I want to do with it (make an ltraj element, calculate the brownian bridge homerange and get the kernel area of it - I take the 95 level): library(adehabitatHR) myframe3ltraj <- as.ltraj(myframesxy,myframestime, id=myframe3$AnimalID) myframeLiker <- liker (myframe3ltraj, sig2=18, rangesig1=c(1,10) ) myframeLiker MyframeBB <- kernelbb(myframe3ltraj, sig1=4.6036, sig2=18) kernel.area(MyframeBB, unout=c("km2") ) With the only difference that I don't want to calculate the homerange for the complete time but for each day. I could use "subset" and do it for every day by hand. But I'd have to do it for three month and then again for several animals. So I thought using a loop for each animal to get the results by date would be much faster. Does anybody have any idea? -- View this message in context: http://r.789695.n4.nabble.com/loop-with-date-tp4650961p4650983.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ 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.