Something like:
newVar <- ifelse(group == 1 & diagnosis == 1, 'positive',
'negative')
[You might want to coerce that to a factor if you wish.]
Andy
> From: Shaw, Philip (NIH/NIMH)
>
> Hi
>
> A very simple question (from a R novice)
>
> How do I create a new variable within R. I have two existing
> variables (eg
> group number 1,2,3 and diagnosis 1,2,3). How would I create
> a new variable
> in which those in group1 with diagnosis 1 are assigned
> 'positive' and the
> remainder are 'negative'??
>
> Many thanks- and sorry it's so simple!
>
> Philip
>
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