Hi Jim,
Thanks for going to the trouble of writing the function. I'll copy and try it.
Gerard
At 06:30 PM 9/7/2007, jim holtman wrote:
>This function should do it for you:
>
>
> > file1 <- read.table(textConnection(" id rx week dv1
>+ 1 1 1 1 1
>+ 2 1 1 2 1
>+ 3 1 1 3 2
>+ 4 2 1 1 3
>+ 5 2 1 2 4
>+ 6 2 1 3 1
>+ 7 3 1 1 2
>+ 8 3 1 2 3
>+ 9 3 1 3 4
>+ 10 4 1 1 2
>+ 11 4 1 2 6
>+ 12 4 1 3 5
>+ 13 5 2 1 7
>+ 14 5 2 2 8
>+ 15 5 2 3 5
>+ 16 6 2 1 2
>+ 17 6 2 2 4
>+ 18 6 2 3 6
>+ 19 7 2 1 7
>+ 20 7 2 2 8
>+ 21 8 2 1 9
>+ 22 9 2 1 4
>+ 23 9 2 2 5"), header=TRUE)
> >
> > mark.function <-
>+ function(df){
>+ df <- df[order(df$id, df$week),]
>+ # create 'diff' of 'id' to determine where the breaks are
>+ breaks <- diff(df$id)
>+ # the first entry will be TRUE, and then every occurance of
>non-zero in breaks
>+ df$first.id <- c(TRUE, breaks != 0)
>+ # the last entry is TRUE and every non-zero breaks
>+ df$last.id <- c(breaks != 0, TRUE)
>+ df
>+ }
> >
> > mark.function(file1)
> id rx week dv1 first.id last.id
>1 1 1 1 1 TRUE FALSE
>2 1 1 2 1 FALSE FALSE
>3 1 1 3 2 FALSE TRUE
>4 2 1 1 3 TRUE FALSE
>5 2 1 2 4 FALSE FALSE
>6 2 1 3 1 FALSE TRUE
>7 3 1 1 2 TRUE FALSE
>8 3 1 2 3 FALSE FALSE
>9 3 1 3 4 FALSE TRUE
>10 4 1 1 2 TRUE FALSE
>11 4 1 2 6 FALSE FALSE
>12 4 1 3 5 FALSE TRUE
>13 5 2 1 7 TRUE FALSE
>14 5 2 2 8 FALSE FALSE
>15 5 2 3 5 FALSE TRUE
>16 6 2 1 2 TRUE FALSE
>17 6 2 2 4 FALSE FALSE
>18 6 2 3 6 FALSE TRUE
>19 7 2 1 7 TRUE FALSE
>20 7 2 2 8 FALSE TRUE
>21 8 2 1 9 TRUE TRUE
>22 9 2 1 4 TRUE FALSE
>23 9 2 2 5 FALSE TRUE
> >
> >
>
>
>On 9/7/07, Gerard Smits <[EMAIL PROTECTED]> wrote:
> > Hi R users,
> >
> > I have a test dataframe ("file1," shown below) for which I am trying
> > to create a flag for the first and last ID record (equivalent to SAS
> > first.id and last.id variables.
> >
> > Dump of file1:
> >
> > > file1
> > id rx week dv1
> > 1 1 1 1 1
> > 2 1 1 2 1
> > 3 1 1 3 2
> > 4 2 1 1 3
> > 5 2 1 2 4
> > 6 2 1 3 1
> > 7 3 1 1 2
> > 8 3 1 2 3
> > 9 3 1 3 4
> > 10 4 1 1 2
> > 11 4 1 2 6
> > 12 4 1 3 5
> > 13 5 2 1 7
> > 14 5 2 2 8
> > 15 5 2 3 5
> > 16 6 2 1 2
> > 17 6 2 2 4
> > 18 6 2 3 6
> > 19 7 2 1 7
> > 20 7 2 2 8
> > 21 8 2 1 9
> > 22 9 2 1 4
> > 23 9 2 2 5
> >
> > I have written code that correctly assigns the first.id and
> last.id variabes:
> >
> > require(Hmisc) #for Lags
> > #ascending order to define first dot
> > file1<- file1[order(file1$id, file1$week),]
> > file1$first.id <- (Lag(file1$id) != file1$id)
> > file1$first.id[1]<-TRUE #force NA to TRUE
> >
> > #descending order to define last dot
> > file1<- file1[order(-file1$id,-file1$week),]
> > file1$last.id <- (Lag(file1$id) != file1$id)
> > file1$last.id[1]<-TRUE #force NA to TRUE
> >
> > #resort to original order
> > file1<- file1[order(file1$id,file1$week),]
> >
> >
> >
> > I am now trying to get the above code to work as a function, and am
> > clearly doing something wrong:
> >
> > > first.last <- function (df, idvar, sortvars1, sortvars2)
> > + {
> > + #sort in ascending order to define first dot
> > + df<- df[order(sortvars1),]
> > + df$first.idvar <- (Lag(df$idvar) != df$idvar)
> > + #force first record NA to TRUE
> > + df$first.idvar[1]<-TRUE
> > +
> > + #sort in descending order to define last dot
> > + df<- df[order(-sortvars2),]
> > + df$last.idvar <- (Lag(df$idvar) != df$idvar)
> > + #force last record NA to TRUE
> > + df$last.idvar[1]<-TRUE
> > +
> > + #resort to original order
> > + df<- df[order(sortvars1),]
> > + }
> > >
> >
> > Function call:
> >
> > > first.last(df=file1, idvar=file1$id,
> > sortvars1=c(file1$id,file1$week), sortvars2=c(-file1$id,-file1$week))
> >
> > R Error:
> >
> > Error in as.vector(x, mode) : invalid argument 'mode'
> > >
> >
> > I am not sure about the passing of the sort strings. Perhaps this is
> > were things are off. Any help greatly appreciated.
> >
> > Thanks,
> >
> > Gerard
> > [[alternative HTML version deleted]]
> >
> > ______________________________________________
> > R-help@stat.math.ethz.ch 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.
> >
>
>
>--
>Jim Holtman
>Cincinnati, OH
>+1 513 646 9390
>
>What is the problem you are trying to solve?
[[alternative HTML version deleted]]
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