On 12/2/2009 3:01 PM, Peter Flom wrote: > Good afternoon > > Running R2.10.0 on Windows > > I have a data frame that includes (among much else) a factor (In_2006) and a > continuous variable (math_3_4). I would like to find the 2 cases for In_2006 > = 0 that are closest to each case where In_2006 = 1. > > My data looks like > > In_2006 math_3_4 > 0 55.1 > 1 51.6 > 1 18.1 > 1 26.6 > 1 14.1 > 1 9.6 > 1 48.9 > 1 12.9 > 0 63.0 > 0 51.8 > > etc. for several hundred rows. > > I would like a new data frame that has all the cases where In_2006 = 1, and > those cases of In_2006 that are closest to those cases
Hi Peter: How about using one of the various matching packages (MatchIt, optmatch, Matching)? For example, something like this: DF <- data.frame(X = rbinom(200, 1, .1), Y = runif(200)) library(MatchIt) DF.match <- matchit(X ~ Y, data=DF, method='optimal', ratio=2) DF[c(rownames(DF.match$match.matrix), c(DF.match$match.matrix)),] hope this helps, Chuck > Thanks in advance > > Peter > > Peter L. Flom, PhD > Statistical Consultant > Website: www DOT peterflomconsulting DOT com > Writing; http://www.associatedcontent.com/user/582880/peter_flom.html > Twitter: @peterflom > > ______________________________________________ > 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. -- Chuck Cleland, Ph.D. NDRI, Inc. (www.ndri.org) 71 West 23rd Street, 8th floor New York, NY 10010 tel: (212) 845-4495 (Tu, Th) tel: (732) 512-0171 (M, W, F) fax: (917) 438-0894 ______________________________________________ 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.
