[R] Better way than an ifelse statement?

[Ista Zahn]

There is a recode function in the Hmisc package that might help:

library(Hmisc)
example$X3 <- recode(example$X2, 1:4, c(-3,-1,1,3))

-Ista

On Thu, Jan 14, 2010 at 2:05 AM, Joshua Wiley <jwiley.psych at gmail.com> wrote:
> Hello All,
>
> I am trying to create a column of weights based off of factor levels
> from another column.  I am using the weights to calculate L scores.
> Here is an example where the first column are scores, the second is my
> "factor" and the third I want to be a column of weights.  I can do
> what I want with an ifelse statement (see below), but I am wondering
> if anyone knows of a cleaner way to do this?
>
> example <- data.frame(cbind(rnorm(4), rep(1:4, 1), c(0)))
>
> example$X3 <- ifelse(example$X2==1, -3, (
> ifelse(example$X2==2, -1, (
> ifelse(example$X2==3, 1, (
> ifelse(example$X2==4, 3, NA))))))) ## this seems sloppy to me
>
>> example
>           X1 X2 X3
> 1  1.75308880  1 -3
> 2 -0.49273616  2 -1
> 3 -0.12446648  3  1
> 4 -0.06417217  4  3
>
>
> Thanks for your help,
>
> Joshua
>
> --
> Joshua Wiley
> Senior in Psychology
> University of California, Riverside
> http://www.joshuawiley.com/
>
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>



-- 
Ista Zahn
Graduate student
University of Rochester
Department of Clinical and Social Psychology
http://yourpsyche.org