This is probably very simple but I'm new to R so apologies for being stupid.
I have some data with No coded as 0 and yes coded as 1.
e.g.
id sex alcohol smoker
1 M 0 1
2 F 1 0
3 M 0 0
I realise I can covert the numerical variable back to a factor by
falcohol<-factor(alcohol,levels=0:1)
levels<-c("No","Yes")
fsmoker<-factor(smoker,levels=0:1)
levels<-c("No","Yes")
but can I do this for all factors using the same levels in a single command
to make it easier (i.e. switch all 0/1, no/yes variables without having to
recode the same factor levels for them all)?
Derek
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one way is the following:
DF <- data.frame(id = 1:6,
sex = gl(2, 3, labels = c("M", "F")),
x = sample(0:1, 6, TRUE), y = sample(0:1, 6, TRUE),
z = rnorm(6))
f <- function (x) {
if (all(unique(x) %in% 0:1))
factor(x, levels = 0:1, labels = c("No", "Yes"))
else
x
}
DF[] <- lapply(DF, f)
I hope it helps.
Best,
Dimitris
On 4/19/2011 10:57 AM, dereksloan wrote:> This is probably very simple but I'm new to R so apologies for being
stupid.
>
> I have some data with No coded as 0 and yes coded as 1.
>
> e.g.
>
> id sex alcohol smoker
> 1 M 0 1
> 2 F 1 0
> 3 M 0 0
>
> I realise I can covert the numerical variable back to a factor by
>
> falcohol<-factor(alcohol,levels=0:1)
> levels<-c("No","Yes")
> fsmoker<-factor(smoker,levels=0:1)
> levels<-c("No","Yes")
>
> but can I do this for all factors using the same levels in a single command
> to make it easier (i.e. switch all 0/1, no/yes variables without having to
> recode the same factor levels for them all)?
>
> Derek
>
> --
> View this message in context:
http://r.789695.n4.nabble.com/Several-factors-same-levels-tp3459878p3459878.html
> Sent from the R help mailing list archive at Nabble.com.
>
> ______________________________________________
> R-help at 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.
>
--
Dimitris Rizopoulos
Assistant Professor
Department of Biostatistics
Erasmus University Medical Center
Address: PO Box 2040, 3000 CA Rotterdam, the Netherlands
Tel: +31/(0)10/7043478
Fax: +31/(0)10/7043014
Web: http://www.erasmusmc.nl/biostatistiek/
On Apr 19, 2011, at 10:57 , dereksloan wrote:> This is probably very simple but I'm new to R so apologies for being stupid. > > I have some data with No coded as 0 and yes coded as 1. > > e.g. > > id sex alcohol smoker > 1 M 0 1 > 2 F 1 0 > 3 M 0 0 > > I realise I can covert the numerical variable back to a factor by > > falcohol<-factor(alcohol,levels=0:1) > levels<-c("No","Yes") > fsmoker<-factor(smoker,levels=0:1) > levels<-c("No","Yes") > > but can I do this for all factors using the same levels in a single command > to make it easier (i.e. switch all 0/1, no/yes variables without having to > recode the same factor levels for them all)?Yes, if they are in the same data frame. The idiom goes roughly like this ix <- c("alcohol", "smoker") new <- paste("f", ix, sep="") dd[new] <- lapply(dd[ix], factor, levels=0:1, labels=c("No","Yes")) (You might store the transformed variables back where they came from, just make sure to do it exactly once! That would avoid creating new variable names and give you a bit more flexibility in the choice of index type. There are also various possibilities to actually compute the indices, e.g. isBin <- function(x) all(na.omit(x) %in% 0:1) ixl <- sapply(dd, isBin) ix <- names(dd)[ixl] ... )> > Derek > > -- > View this message in context: http://r.789695.n4.nabble.com/Several-factors-same-levels-tp3459878p3459878.html > Sent from the R help mailing list archive at Nabble.com. > > ______________________________________________ > R-help at 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.-- Peter Dalgaard Center for Statistics, Copenhagen Business School Solbjerg Plads 3, 2000 Frederiksberg, Denmark Phone: (+45)38153501 Email: pd.mes at cbs.dk Priv: PDalgd at gmail.com