Hi: Letting d1 and d2 be your two data frames,
> merge(d1, d2, by.x = 'x1', by.y = 'num', all.x = TRUE)[, c(2, 4, 3)] grpnum uniqueid x2 1 D <NA> 276 2 B <NA> 898 3 A GHU82RK02HD7D6 334 4 C GHU82RK02IXPC7 4077 If you want x1 to be the variable name for the new dataset, then dmerge <- merge(d1, d2, by.x = 'x1', by.y = 'num', all.x = TRUE)[, c(2, 4, 3)] names(dmerge)[2] <- 'x1' HTH, Dennis On Wed, Jun 1, 2011 at 11:30 AM, mcginnis21 <mcgin...@montana.edu> wrote: > Hoping someone out there can help me...this seems like an easy task but I > can't figure it out... > > I want to replace variables in one dataset (Dataset1) with a variable from > another dataset (Dataset2). > All the values for variables x1 and x2 in Dataset1 have a unique match to > the variable uniquenum in Dataset2. For example, in Dataset1 grpnum A has a > value of 343 for variable x1. In Dataset2, 343 will only be found once for > variable uniquenum. I would like to create a new dataset where the variable > x1 from Dataset1 will be replaced by uniqueid from Dataset2. So variable x1 > for grpnum A now would equal GHU82RK02HD7D6 rather than 343. Below is an > abbreviated example from my datasets to show what I’m trying to do rather > than explain in words because I’m not sure my question is coming across very > clearly. I have about 100 columns in Dataset1 (x1, x2, etc.) and the > variable uniquenum in Dataset2 has about 4,000 values. > > Dataset1 > grpnum x1 x2 > A 343 334 > B 313 898 > C 4076 4077 > D 275 276 > > Dataset2 > unique num uniqueid > 343 GHU82RK02HD7D6 > 4076 GHU82RK02IXPC7 > 4077 GHU82RK02HICZ2 > 261 GHU82RK02FLOFU > 4100 GHU82RK02IDO7K > 4101 GHU82RK02HQYQL > 4102 GHU82RK02GADV1 > 4103 GHU82RK02G7RQH > 4104 GHU82RK02HQD2E > > > > NewDataset > grpnum x1 x2 > a GHU82RK02HD7D6 Na > b Na Na > c GHU82RK02IXPC7 GHU82RK02HICZ2 > d Na Na > > > > Thanks for your time and thoughts. I hope someone can help! > > > > -- > View this message in context: > http://r.789695.n4.nabble.com/Replacing-variables-in-one-dataset-with-those-from-another-tp3566552p3566552.html > Sent from the R help mailing list archive at Nabble.com. > > ______________________________________________ > 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.