Greg Snow-2 wrote: "You are suffering from the fact that the longest distance between 2 points is a shortcut.
The df$column notation is a shortcut for df[[column]] that has some nice properties, but the shortcut gets in the way when you want to do something more structured. Try qq1[[z]]==y and avoid all that pasting, parsing, and evaluating. " My response: Unfortunately I find it to be not correct and unfortunately I see no way to avoid pasting parsing and evaluating in order to have functions that does simple things in R. temp<-qq1[qq1$PrimaryConditionGroup=="AMI",] has no error when temp<-qq1[qq1[[PrimaryConditionGroup]]=="AMI",] cause the following error announcement "Error in (function(x, i, exact) if (is.matrix(i)) as.matrix(x)[[i]] else .subset2(x, : object 'PrimaryConditionGroup' not found" I found no way to replace the function that was in the subject of this thread by something simpler(and here is the function again) > ugly<-function(y,z) > { > text1<-paste("temp<-qq1[qq1$",z,sep="") > text1<-paste(text1,"==y",sep="") > text1<-paste(text1,",]",sep="") > eval(parse(text=text1)) > temp<<-temp > } -- View this message in context: http://r.789695.n4.nabble.com/How-to-translate-string-to-variable-inside-a-command-in-an-easy-way-in-R-tp3645594p3664747.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.