On Dec 6, 2013, at 11:27 AM, Julio Sergio Santana wrote: > I have a data frame whose first colum contains the names of the variables > and whose second colum contains the values to assign to them: > > : kkk <- data.frame(vars=c("var1", "var2", "var3"), > vals=c(10, 20, 30), stringsAsFactors=F) > > If I do > > : assign(kkk$vars[1], kkk$vals[1]) > > it works > > : var1 > [1] 10 > > However, if I try with mapply this is what I get: > > : mapply(assign, kkk$vars, kkk$vals) > var1 var2 var3 > 10 20 30 > : var2 > Error: object 'var2' not found > > Maybe I have not undestand how mapply and assign work. Do you have > any comments?
I think you will find that the value returned from the mapply call was a three element list with the desired names and values ... except you then gave that enclosing list no name and it will be garbage-collected. If you want to have 'assign' do its magic into the global environment, then you need to supply 'mapply' a MoreArgs argument on the other side of the ellipsis: Usage: mapply(FUN, ..., MoreArgs = NULL, SIMPLIFY = TRUE, USE.NAMES = TRUE) So what happens if you try this: mapply(assign, kkk$vars, kkk$vals, MoreArgs = list(envir = .GlobalEnv) -- David Winsemius Alameda, CA, USA ______________________________________________ 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.