# [R] Several factors same levels

Dimitris Rizopoulos d.rizopoulos at erasmusmc.nl
Tue Apr 19 13:58:40 CEST 2011

```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.
>
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> R-help at r-project.org mailing list
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> 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/

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