I have two dataframe columns of POXIXct data/times that include seconds. I got them into this format using for example zsort$ETA <- as.POSIXct(as.character(zsort$ETA), format="%m/%d/%Y %H:%M:%S")
My problem is that when I subtract the two columns, sometimes the difference is given in seconds, and sometimes it is given in minutes. I don't care which it is, but I need to know which one I will get. DateTime ETA 2010-05-16 02:19:56 2010-05-16 03:46:35 ... Browse[1]> mins = zsort$ETA - zsort$DateTime Browse[1]> mins Time differences in hours [1] 1.444167 2.685000 3.077222 3.210278 3.248056 3.281944 3.281944 3.360278 3.360278 3.582778 4.574444 5.506111 5.857778 6.150278 6.150278 6.243056 6.243889 6.248056 6.248611 6.248611 6.356667 attr(,"tzone") But sometimes the answer is in seconds. # make a column with the minutes before landing >zsort$MinBeforeLand = zsort$ETA - zsort$DateTime > zsort$MinBeforeLand Time differences in secs [1] -50 136 221 878 1192 2263 3296 3959 4968 5846 8709 11537 12198 12442 12642 15952 18273 19952 20538 How do I specify the resultant units? Thanks, Jim Rome ______________________________________________ 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.