[R] Using if

Sarah Goslee sarah.goslee at gmail.com
Tue Nov 20 20:21:26 CET 2012


Hi,

Thanks for providing a reproducible example.

On Tue, Nov 20, 2012 at 2:08 PM, Virgile Capo-Chichi
<vcapochichi at gmail.com> wrote:
> Dear R users,
>
> As a new comer to R, I would like to create a new variable using if
> statements but don't know how to do it. Basically, I have two variables
> (EvHint and MinTex). I want to create a third variable called RiskTest.
>
> In SPSS, my syntax would look like
>
> Compute RiskTest=0.
> if (EvHint=1 & MinTex=1) RiskTest=1.
>
> Question: How do I do this with R?
>
> My Data
>
> EvHint<-c(0, 0, 0, 1, 0, 1, 1, 0, 1, 1, 1, 1, 1, 0, 1, 0, 0, 1, 0, 0)
> MinTex<-c(0, 0, 1, 1, 0, 1, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0)

In this case,

RiskTest <- EvHint * MinTex

In the more general case,
RiskTest <- ifelse(EvHint == 1 & MinTex == 1, 1, 0)

Note that the test for equality is == and not =

You should probably read the Intro to R that came with your
installation and is available online.

--
Sarah Goslee
http://www.functionaldiversity.org




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