> -----Original Message----- > From: r-help-boun...@r-project.org > [mailto:r-help-boun...@r-project.org] On Behalf Of sugo > Sent: Wednesday, September 02, 2009 4:51 PM > To: r-help@r-project.org > Subject: [R] diff of two timestamps > > > Hi all, > > I have the following problem: I have a csv-file consisting of > timestamp > values (no dates), e.g.: > Timestamp1;Timestamp2; > 05:24:43;05:25:05; > 15:47:02;15:47:22; > 18:36:05;18:36:24; > 15:21:24;15:22:04; > > I need a vector with the difference of the two timestamps, so > I read the > data with the read.csv-function: > myObj <- read.csv("file.csv",header=TRUE,sep=";"). > > I have then tried unsuccessfully to convert the data to time > format (e.g. > using the strptime function like date1 <- > strptime(myObj[0],format="%H:%M:%S")) to be able to perform a datediff > operation.
R indices start at 1, not 0, and you should use myObj[,1] to refer to the first column (myObj[1] means a data.frame containing one column, myObj[,1] means the first column itself). myObj$Timestamp1 and myObj[,"Timestamp1"] give that column as well. Hence if you want to use numerical indices try > strptime(myObj[,1],format="%H:%M:%S") [1] "2009-09-02 05:24:43" "2009-09-02 15:47:02" "2009-09-02 18:36:05" [4] "2009-09-02 15:21:24" but replacing the myObj[,1] with myObj$Timestamp1 will make things clearer. with() lets you save some typing by eliminating the repeated mObj$'s. > with(myObj, strptime(Timestamp2,format="%H:%M:%S") - + strptime(Timestamp1,format="%H:%M:%S")) Time differences in secs [1] 22 20 19 40 attr(,"tzone") [1] "" Bill Dunlap TIBCO Software Inc - Spotfire Division wdunlap tibco.com > > I would be very grateful if anybody could give me some assistance. > > Thanks in advance, > Ieyasu > -- > View this message in context: > http://www.nabble.com/diff-of-two-timestamps-tp25267603p25267603.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. > ______________________________________________ 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.
