# [R] Creat new column based on condition

Gabor Grothendieck ggrothendieck at gmail.com
Fri Apr 21 22:40:14 CEST 2006

```DF <- data.frame(V1 = c(10, 20, 30, 10, 10, 20))
DF\$V2 <- with(DF, 4 * (V1 == 10) + 6 * (V1 == 20) + 10 * (V1 == 30))
DF\$V3 <- c(4, 6, 10)[DF\$V1/10]

or

DF <- data.frame(V1 = c(10, 20, 30, 10, 10, 20))
DF <- transform(DF, V2 = 4 * (V1 == 10) + 6 * (V1 == 20) + 10 * (V1 == 30),
V3 = c(4, 6, 10)[V1/10])

On 4/21/06, Sachin J <sachinj.2006 at yahoo.com> wrote:
>
> Hi Gabor,
>
> The first one works fine. Just out of curiosity, in second solution: I dont
> want to create a matrix. I want to add a new column to the existing
> dataframe (i.e. V2 based on the values in V1). Is there a way to do it?
>
> TIA
> Sachin
>
>
>
> Gabor Grothendieck <ggrothendieck at gmail.com> wrote:
>
> Try:
>
> V1 <- matrix(c(10, 20, 30, 10, 10, 20), nc = 1)
>
> V2 <- 4 * (V1 == 10) + 6 * (V1 == 20) + 10 * (V1 == 30)
>
> or
>
> V2 <- matrix(c(4, 6, 10)[V1/10], nc = 1)
>
> On 4/21/06, Sachin J wrote:
> > Hi,
> >
> > How can I accomplish this task in R?
> >
> > V1
> > 10
> > 20
> > 30
> > 10
> > 10
> > 20
> >
> > Create a new column V2 such that:
> > If V1 = 10 then V2 = 4
> > If V1 = 20 then V2 = 6
> > V1 = 30 then V2 = 10
> >
> > So the O/P looks like this
> >
> > V1 V2
> > 10 4
> > 20 6
> > 30 10
> > 10 4
> > 10 4
> > 20 6
> >
> >
> > Sachin
> >
> > __________________________________________________
> >
> >
> >
> > [[alternative HTML version deleted]]
> >
> > ______________________________________________
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> >
>
>
>
>
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```