Dr. LaBudde, Perhaps
as.numeric(as.character(x)) is what you are looking for. HTH, Jorge On Sun, Jun 5, 2011 at 12:31 AM, Robert A. LaBudde <> wrote: > I have a data frame: > > > head(df) > Time Temp Conc Repl Log10 > 1 0 -20 H 1 6.406547 > 2 2 -20 H 1 5.738683 > 3 7 -20 H 1 5.796394 > 4 14 -20 H 1 4.413691 > 5 0 4 H 1 6.406547 > 7 7 4 H 1 5.705433 > > str(df) > 'data.frame': 177 obs. of 5 variables: > $ Time : Factor w/ 4 levels "0","2","7","14": 1 2 3 4 1 3 4 1 3 4 ... > $ Temp : Factor w/ 4 levels "-20","4","25",..: 1 1 1 1 2 2 2 3 3 3 ... > $ Conc : Factor w/ 3 levels "H","L","M": 1 1 1 1 1 1 1 1 1 1 ... > $ Repl : Factor w/ 5 levels "1","2","3","4",..: 1 1 1 1 1 1 1 1 1 1 ... > $ Log10: num 6.41 5.74 5.8 4.41 6.41 ... > > levels(df$Temp) > [1] "-20" "4" "25" "45" > > levels(df$Time) > [1] "0" "2" "7" "14" > > As you can see, "Time" and "Temp" are currently factors, not numeric. > > I would like to change these columns into numerical ones. > > df$Time<- as.numeric(df$Time) > > doesn't work, as it changes to the factor level indices (1,2,3,4) instead > of the values (0,2,7,14). > > There must be a direct way of doing this in R. > > I tried recode() in 'car': > > > df$Temp<- recode(df$Temp, '1=-20;2=25;3=4;4=45',as.factor.result=FALSE) > > head(df) > Time Temp Conc Repl Freq > 1 0 -20 H 1 6.406547 > 2 2 -20 H 1 5.738683 > 3 7 -20 H 1 5.796394 > 4 14 -20 H 1 4.413691 > 5 0 45 H 1 6.406547 > 7 7 45 H 1 5.705433 > > but note that the values for 'Temp' in rows 5 and 7 are 45 and not 4, as > expected, although the result is numeric. The same happens if I use the > order given by levels(df$Temp) instead of the sort order in the recode() 2nd > argument. > > Any hints? > ================================================================ > Robert A. LaBudde, PhD, PAS, Dpl. ACAFS e-mail: r...@lcfltd.com > Least Cost Formulations, Ltd. URL: http://lcfltd.com/ > 824 Timberlake Drive Tel: 757-467-0954 > Virginia Beach, VA 23464-3239 Fax: 757-467-2947 > > "Vere scire est per causas scire" > > ______________________________________________ > 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. > [[alternative HTML version deleted]] ______________________________________________ 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.
