Thank you!
From: William Dunlap [mailto:wdun...@tibco.com] Sent: Friday, January 23, 2015 7:14 PM To: Tan, Richard Cc: r-help@R-project.org Subject: Re: [R] get latest dates for different people in a dataset Here is one way. Sort the data.frame, first by Name then break ties with CheckInDate. Then choose the rows that are the last in a run of identical Name values. > txt <- "Name CheckInDate Temp + John 1/3/2014 97 + Mary 1/3/2014 98.1 + Sam 1/4/2014 97.5 + John 1/4/2014 99" > d <- read.table(header=TRUE, colClasses=c("character","character","numeric"), > text=txt) > d$CheckInDate <- as.Date(d$CheckInDate, as.Date, format="%d/%m/%Y") > isEndOfRun <- function(x) c(x[-1] != x[-length(x)], TRUE) > dSorted <- d[order(d$Name, d$CheckInDate), ] > dLatestVisit <- dSorted[isEndOfRun(dSorted$Name), ] > dLatestVisit Name CheckInDate Temp 4 John 2014-04-01 99.0 2 Mary 2014-03-01 98.1 3 Sam 2014-04-01 97.5 Bill Dunlap TIBCO Software wdunlap tibco.com<http://tibco.com> On Fri, Jan 23, 2015 at 3:43 PM, Tan, Richard <r...@panagora.com<mailto:r...@panagora.com>> wrote: Hi, Can someone help for a R question? I have a data set like: Name CheckInDate Temp John 1/3/2014 97 Mary 1/3/2014 98.1 Sam 1/4/2014 97.5 John 1/4/2014 99 I'd like to return a dataset that for each Name, get the row that is the latest CheckInDate for that person. For the example above it would be Name CheckInDate Temp John 1/4/2014 99 Mary 1/3/2014 98.1 Sam 1/4/2014 97.5 Thank you for your help! Richard [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org<mailto:R-help@r-project.org> mailing list -- To UNSUBSCRIBE and more, see 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 -- To UNSUBSCRIBE and more, see 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.