Dear Jeff, Assuming that the column named "z" in the matrix data2 already exists and has arbitrary content (such as 0's or NA's), how about the following?
data2[,"z"] <- data1[data2[,"ID"], "z"] I hope this helps, John -------------------------------- John Fox Department of Sociology McMaster University Hamilton, Ontario Canada L8S 4M4 905-525-9140x23604 http://socserv.mcmaster.ca/jfox -------------------------------- > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Jeffrey Moore > Sent: Friday, February 10, 2006 9:23 PM > To: [email protected] > Cc: [EMAIL PROTECTED] > Subject: [R] how do I "relate" tables in R? > > Hi all, > > I'm new to the list...pretty new at learning to code in R... > > Is there a way to relate 2 different arrays in R? > > Hypothetical example: > > data1 > ID z > 1 100 > 2 250 > 3 75 > 4 12 > 5 89 > > data2 > ID z > 1 > 1 > 1 > 1 > 2 > 3 > 4 > 3 > 4 > 5 > 5 > 5 > etc. > > Goal is to fill column z in data2 with appropriate z-values > from data1 that correspond to a given ID. > > I'm looking for something akin to a relational database, or a > lookup table in Excel. > > I can construct a simple for-loop (with if else statement) to > fill the z-column in data2, but in my case data2 is 150,000 > records long, so this approach is not efficient. > > Thanks for any help > Jeff > > ****************************************** > Jeffrey Moore, Ph.D. > Postdoctoral Research Scientist > Duke Center for Marine Conservation > Duke University Marine Laboratory > 135 Duke Marine Lab Road > Beaufort, NC 28516 > Phone: (252) 504-7653 > Fax: (252) 504-7689 > Email: [EMAIL PROTECTED] > ***************************************** > > > [[alternative HTML version deleted]] > > ______________________________________________ > [email protected] mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide! > http://www.R-project.org/posting-guide.html ______________________________________________ [email protected] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
