[R] Using if

[Peter Alspach]

Tena koe

If the vectors are long and time is an issue, it might be better to avoid the use of ifelse().

Try:
set.seed(0)
EvHint <- rbinom(10^7, 1, 0.5)
MinTex <- rbinom(10^7, 1, 0.5)
system.time(RiskTest0 <- ifelse(EvHint==1 & MinTex==1, 1, 0))
system.time({
RiskTest1 <- rep(0, length(EvHint))
RiskTest1[EvHint==1 & MinTex==1] <- 1})
all.equal(RiskTest0, RiskTest1)

Hei kona ra ....

Peter Alspach

-----Original Message-----
From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org] On Behalf Of Jeff Newmiller
Sent: Wednesday, 21 November 2012 8:18 a.m.
To: Virgile Capo-Chichi; r-help at r-project.org
Subject: Re: [R] Using if

?ifelse

Quite distinct from if () {} else {}.
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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)
>
>Thanks, V
>
>	[[alternative HTML version deleted]]
>
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