i don't think i understood what you were trying to do, atleast based on Henrique's solution which I haven't cut and pasted yet in order to understand. Did Henrique's solution do what you wanted ?
On Wed, Aug 13, 2008 at 2:45 PM, Ralph S. wrote: I tried this - I get an empty set: <0 rows> (or 0-length row.names) I guess this happens because the z variable takes only one value per row?? What works is: DFsub<-DF[DF$z == 1 | DF$z == 2,] but then, I do not eliminate the entries where there is only one entry for z given an a and c combination. Any idea what to do? -Ralph > Date: Wed, 13 Aug 2008 13:05:25 -0500 From: [EMAIL PROTECTED] > Subject: RE: [R] subsetting matrix according to columns with character > index To: [EMAIL PROTECTED] > it must be a dataframe so, if it was DF, then, assuming i understand > what you want then either of the following should work: > DFsub<-DF[DF$z == 1 & DF$z == 2,] > or > DFsub<-subset(DF, z == 1 & z == 2 ) > > On Wed, Aug 13, 2008 at 2:00 PM, Ralph S. wrote: >> Hi, >> I have a long matrix of the following form which I would like to >> subset according to the third column: >> [x y z]: >> a1 c1 1 a1 c1 2 a2 c1 1 a1 c2 1 a1 c2 2 . . . >> >> The first two columns a characters ai and cj. >> I would like to keep all the rows where there are two entries for z, >> 1 and 2. >> That is, I want: a1 c1 1 a1 c1 2 a1 c2 1 a1 c2 2 . . . >> I try to use something like df[by(df,c(df$x,df$y),sum(z)==3),] but >> that only gives me one line of data per x y combination. >> Is there an easy way of coding to keep all rows for a and c >> combinations where z has entries both 1 and 2? Many thanks, >> Ralph >> _________________________________________________________________ >> >> LM_WLYIA_whichathlete_us >> ______________________________________________ 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. ___________________________________ Your PC, mobile phone, and online services work together like never before. See how Windows® fits your life <http://clk.atdmt.com/MRT/go/108587394/direct/01/> [[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.
