Hi Marna, I was able to have another look at it. I think this is what you want except for the column names (I'm lazy):
dAT<-structure(list(Id = structure(c(1L, 2L, 3L, 4L, 1L, 2L, 5L, 4L, 1L, 6L, 6L, 3L, 4L, 1L), .Label = c("a", "b", "c", "e", "f", "m"), class = "factor"), date = structure(c(1L, 1L, 1L, 5L, 4L, 1L, 5L, 5L, 3L, 1L, 2L, 7L, 6L, 8L), .Label = c("1-Jan-18", "1-Jul-18", "10-Mar-18", "15-Jan-18", "2-Jan-18", "27-Jan-18", "3-Jan-18", "7-Mar-19"), class = "factor")), .Names = c("Id", "date"), class = "data.frame", row.names = c(NA,-14L)) dAT$date<-as.Date(dAT$date,"%d-%b-%y") diffs<-function(x,maxn) return(diff(x)[1:maxn]) mindate<-function(x) return(min(x)) datediffs<-aggregate(dAT$date,list(dAT$Id),diffs,3) initdates<-as.character(as.Date(as.vector(by(dAT$date,dAT$Id,min)), origin=as.Date("1970-01-01"))) Result<-data.frame(Id=datediffs$Group.1,Release=initdates, 'T1-T2'=datediffs$x[,1],'T1-T3'=datediffs$x[,1]+datediffs$x[,2], 'T1-T4'=datediffs$x[,1]+datediffs$x[,2]+datediffs$x[,3], 'T2-T3'=datediffs$x[,2],'T2-T4'=datediffs$x[,2]+datediffs$x[,3]) Jim On Sat, May 4, 2019 at 7:57 AM Jim Lemon <drjimle...@gmail.com> wrote: > > Hi Marna, > You can get the information you need with this: > > dAT$date<-as.Date(dAT$date,"%d-%b-%y") > diffs<-function(x,maxn) return(diff(x)[1:maxn]) > initdate<-function(x) return(min(x)) > datediffs<-aggregate(dAT$date,list(dAT$Id),diffs,3) > > I can't do the manipulation of the resulting values at the moment, but > can work it out later if necessary. > > Jim > > On Sat, May 4, 2019 at 5:24 AM Marna Wagley <marna.wag...@gmail.com> wrote: > > > > Hi R User. > > I have a date set in which I wanted to find the duration (period) between > > released time and detection time for each individual. Is there any simplest > > way to create a matrix? > > I appreciate your help. > > > > Thanks, > > MW > > -------------- > > Here is the example data, > > > > dAT<-structure(list(Id = structure(c(1L, 2L, 3L, 4L, 1L, 2L, 5L, 4L, > > > > 1L, 6L, 6L, 3L, 4L, 1L), .Label = c("a", "b", "c", "e", "f", > > > > "m"), class = "factor"), date = structure(c(1L, 1L, 1L, 5L, 4L, > > > > 1L, 5L, 5L, 3L, 1L, 2L, 7L, 6L, 8L), .Label = c("1-Jan-18", "1-Jul-18", > > > > "10-Mar-18", "15-Jan-18", "2-Jan-18", "27-Jan-18", "3-Jan-18", > > > > "7-Mar-19"), class = "factor")), .Names = c("Id", "date"), class = > > "data.frame", row.names = c(NA, > > > > -14L)) > > > > > > #and the results looks like > > > > > > Result<-structure(list(Id = structure(1:6, .Label = c("a", "b", "c", > > > > "e", "f", "m"), class = "factor"), intial.released.date = structure(c(1L, > > > > 1L, 1L, 2L, 2L, 1L), .Label = c("1-Jan-18", "2-Jan-18"), class = "factor"), > > > > duration.between.t2.and.t1 = c(14L, 0L, 2L, 0L, NA, 181L), > > > > duration.between.t3.and.t1 = c(68L, NA, NA, 25L, NA, NA), > > > > duration.between.t4.and.t1 = c(430L, NA, NA, NA, NA, NA), > > > > duration.between.t3.and.t2 = c(54L, NA, NA, NA, NA, NA), > > > > duration.between.t4.and.t2 = c(416L, NA, NA, NA, NA, NA)), .Names = c( > > "Id", > > > > "intial.released.date", "duration.between.t2.and.t1", > > "duration.between.t3.and.t1", > > > > "duration.between.t4.and.t1", "duration.between.t3.and.t2", > > "duration.between.t4.and.t2" > > > > ), class = "data.frame", row.names = c(NA, -6L)) > > > > [[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. ______________________________________________ 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.