Jagz, Assuming that your data frame is called df, try this ...
tapply(df$Value, list(df$ID1, df$ID2), mean) Jean `·.,, ><(((º> `·.,, ><(((º> `·.,, ><(((º> Jean V. Adams Statistician U.S. Geological Survey Great Lakes Science Center 223 East Steinfest Road Antigo, WI 54409 USA 715-627-4317, ext. 3125 (Office) 715-216-8014 (Cell) 715-623-6773 (FAX) http://www.glsc.usgs.gov (GLSC web site) http://profile.usgs.gov/jvadams (My homepage) jvad...@usgs.gov (E-mail) From: Jagz Bell <jagzb...@yahoo.com> To: "r-help@R-project.org" <r-help@r-project.org> Date: 08/02/2011 12:13 PM Subject: [R] Data frame to matrix - revisited Sent by: r-help-boun...@r-project.org Hi, I've tried to look through all the previous related Threads/posts but can't find a solution to what's probably a simple question. I have a data frame comprised of three columns e.g.: ID1 ID2 Value a b 1 b d 1 c a 2 c e 1 d a 1 e d 2 I'd like to convert the data to a matrix i.e.: a b c d e a n/a 1 2 1 n/a b 1 n/a n/a 1 n/a c 2 n/a n/a n/a 1 d 1 1 n/a n/a 2 e n/a n/a 1 2 n/a Any help is much appreciated, Jagz ______________________________________________ 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. [[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.
