merge(Whole,Where.Lesion2) gives the intersections (ID/Date/Segment/Slice, i.e. the first 4 columns), except that the merge function drops the original row.names in the dataframe "Whole".
Now, the question evolves to finding row.names of one data frame that matches any of the rows in another dataframe. Gordon On Sat, Mar 13, 2010 at 7:54 PM, Junqian Gordon Xu <xjq...@gmail.com> wrote: > I have a multilevel dataframe (df): > > ID Date Segment Slice Tract Lesion > 1 CSPP005 12/4/2007 1 1 LCST 0 > 2 CSPP005 12/4/2007 1 1 LPC 2 > 3 CSPP005 12/4/2007 1 1 RPC 3 > 4 CSPP005 12/4/2007 1 1 RCST 1 > 5 CSPP005 12/4/2007 1 1 LGM 0 > 6 CSPP005 12/4/2007 1 1 RGM 0 > 7 CSPP005 12/4/2007 1 1 Whole NA > > The five levels are: > > ID->Date->Segment->Slice->Tract > > The observation variable is: Lesion > > What I want to do is (in pseudo code) > > if (any of the Tract (for a given ID, Date, Segment, and Slice), > which( Lesion == 2) ) > df [ for that particular (ID, Date,Segment, and slice) , > which(Tract == Whole) ] $Lesion <- 2 > else > df [ for that particular (ID, Date,Segment, and slice) , > which(Tract == Whole) ] $Lesion <- 0 > > > > I started with (don't know if this is the right path), > > Lesion2<-df[which(df$Lesion == 2),] > Where.Lesion2<-unique(Lesion2[,1:4]) > Whole<-subset(df, Tract == "Whole") > > But stuck at how to match the ID/Date/Segment/Slice from Where.Lesion2 to > Whole. > > Regards > Gordon > ______________________________________________ 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.
