Hi JR, There are few ways to do what you asked for, so here is one suggestion using tapply:
Age <- c(48, 57, 56, 76, 76, 66, 70, 14, 7, 3, 62, 62, 30, 10, 7, 53, 44, 29, 46, 47, 15, 13, 84, 77, 26) SerialNo <- c(001147, 005979, 005979, 006128, 006128, 007004, 007004, 007004, 007004, 007004, 007438, 007438,009402,009402, 009402, 012693, 012693, 012693, 014063,014063, 014063, 014063, 014811, 014811,016570) TestSet <- data.frame(Age,SerialNo) TestSet$IsHead <- do.call(c, tapply(Age, SerialNo, function(x) x >= max(x) ) ) TestSet See ?tapply, ?do.call as well as ?ave for more information. HTH, Jorge On Mon, Aug 3, 2009 at 3:04 PM, PDXRugger <> wrote: > > COnsider the following: > > Age<-c(48, 57, 56, 76, 76, 66, 70, 14, 7, 3, 62, 62, 30, 10, 7, 53, 44, > 29, 46, 47, 15, 13, 84, 77, 26) > > SerialNo<-c(001147, 005979, 005979, 006128, 006128, 007004, 007004, 007004, > 007004, 007004, 007438, 007438,009402,009402, 009402, 012693, 012693, > 012693, 014063,014063, 014063, 014063, 014811, 014811,016570) > > TestSet<-cbind(Age,SerialNo) > > TestSet<-data.frame(TestSet) > > I am looking to create a third column titled "IsHead". This column would > be > either TRUE or FALSE depending on whether the Age variable was the greatest > for that set of SerialNo's. So for the above i would return: > > Age SerialNo IsHead > 48 1147 TRUE > 57 5979 TRUE > 56 5979 FALSE > 76 6128 TRUE > 76 6128 FALSE > 66 7004 FALSE > 70 7004 TRUE > 14 7004 FALSE > 7 7004 FALSE > 3 7004 FALSE > > I am thinking this is simple but cannot get my own code to work. Thanks > for > any insights. > > JR > -- > View this message in context: > http://www.nabble.com/Truncating-based-on-attribute-range-and-serial-no-tp24796313p24796313.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. > [[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.
