> The variables mma, and dma are actually numerical variables but in the > dataframe, they are represented as "characters". I tried to change the type > of the variables (from character to numeric) using the edit function (and > bringing up the data grid where then I made changes), but the changes were > not saved. I tried > > mma1 <- as.numeric(mma)
i'm not sure understanding your problem correct, but is it possible that you forget the data.frame ,suppose your data.frame is df df$mma <- as.numeric (mma) should work df$mma[df$mma == 0 ] <- 1 #"or any other value" regards,christian ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help