Dear All, on rbind:ing together a number of data.frames, I found that character variables are converted into factors. Since this occurred for a data identifier, it was a little inconvenient and, to me, unexpected. (The help page explains the general procedure used. I also found that on forming a data frame, character variables are converted to factors.
The help page on read.table has the 'as.is' argument, which I suppose kind of suggests that character variables tend to get converted into factors. Is there such a "preference" for factors and should this behaviour be expected? Example code d1 <- data.frame(id =letters[1:20], x = runif(20)) d2 <- data.frame(id =paste(letters[1:20],letters[1:20], sep = ""), x = rexp(20)) d3 <- rbind(d1, d2) str(d1) # <- id is factor str(d2) # <- id is factor str(d3) # <- id is factor d1[["id"]] <- as.character(d1[["id"]]) d2[["id"]] <- as.character(d2[["id"]]) d3 <- rbind(d1, d2) str(d1) # <- id is character str(d2) # <- id is character str(d3) # <- id is factor Regards, Markus -- Markus Jäntti <[EMAIL PROTECTED]> Statistics Finland ______________________________________________ [EMAIL PROTECTED] mailing list http://www.stat.math.ethz.ch/mailman/listinfo/r-help
