[R] ifelse with a factor variable

[Liaw, Andy]

Does the following help you?

> x <- factor(c("A", "B", NA))
> levels(x) <- c(levels(x), "unknown")  # add an "unknown" level
> x[is.na(x)] <- "unknown"  # change NAs to "unknown"
> x
[1] A       B       unknown
Levels: A B unknown

Andy

> -----Original Message-----
> From: Goran Brostrom [mailto:gb at tal.stat.umu.se] 
> Sent: Tuesday, October 28, 2003 3:36 PM
> To: r-help at stat.math.ethz.ch
> Subject: [R] ifelse with a factor variable
> 
> 
> 'ifelse' changes factors to character vectors (R-1.7.1, Linux):
> 
> > table(bal$soc.40)
> 
>           tax         noble semi-landless      landless       unknown 
>          4035          5449         13342          9348             0 
> 
> 
> > blah <- ifelse(is.na(bal$soc.40), "unknown", bal$soc.40)
> > table(blah)
> blah
>       1       2       3       4 unknown 
>    4035    5449   13342    9348    7970 
> 
> How do I get what I want (I mean: simply)? Upgrade to 1.8.0?
> 
> Göran
> 
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list 
> https://www.stat.math.ethz.ch/mailman/listinfo> /r-help
>