or the exactly equivalent form: x[x$X1 %in% unique(x[x$X2>0,"X1"]), ]
Patrizio 2009/4/2 Nutter, Benjamin <nutt...@ccf.org>: > x <- > data.frame(matrix(c(rep(11,4),rep(12,3),rep(13,3),rep(0,3),1,rep(0,4),re > p(1,2)),ncol=2)) > > id.keep <- unique(subset(x,X2>0)$X1) > > x2 <- subset(x,X1 %in% id.keep) > > x2 > > -----Original Message----- > From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] > On Behalf Of Stephan Lindner > Sent: Thursday, April 02, 2009 11:26 AM > To: r-h...@stat.math.ethz.ch > Subject: [R] Selecting all rows of factors which have at least one > positive value? > > Dear all, > > I'm trying to select from a dataframe all rows which correspond to a > factor (the id variable) for which there exists at least one positive > value of a certain variable. As an example: > > x <- > data.frame(matrix(c(rep(11,4),rep(12,3),rep(13,3),rep(0,3),1,rep(0,4),re > p(1,2)),ncol=2)) > >> x > > > X1 X2 > 1 11 0 > 2 11 0 > 3 11 0 > 4 11 1 > 5 12 0 > 6 12 0 > 7 12 0 > 8 13 0 > 9 13 1 > 10 13 1 > > > and I want to select all rows pertaining to factor levels of X1 for > which exists at least one "1" for X2. To be clear, I want rows 1:4 > (since there exists at least one observation for X1==11 for which > X2==1) and rows 8:10 (likewise). > > It is easy to obtain the corresponding factor levels (i.e., > unique(x$X1[x$X2==1])), but I got stalled selecting the corresponding > rows. I tried grep, but then I have to loop and concatenate the > resulting vector. Any ideas? > > > Thanks a lot! > > > Stephan > > > > > > -- > ----------------------- > Stephan Lindner > University of Michigan > > ______________________________________________ > 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. > > > =================================== > > P Please consider the environment before printing this e-mail > > Cleveland Clinic is ranked one of the top hospitals > in America by U.S. News & World Report (2008). > Visit us online at http://www.clevelandclinic.org for > a complete listing of our services, staff and > locations. > > > Confidentiality Note: This message is intended for use\...{{dropped:13}} > > ______________________________________________ > 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. > ______________________________________________ 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.
