[R] If condition using accessors

Peter Ehlers ehlers at ucalgary.ca
Fri Nov 27 13:45:23 CET 2009


Vitória Magalhães Piai wrote:
> Hi,
> 
> I'm quite new using R and have got no one to help me get through it. 
> Hopefully someone can help me with one problem I've been struggling with 
> for the last hours!!
> (Sorry if I'm using the wrong terminology as well!)
> 
> I have a data matrix in which SIE is one of my variables. What I need to 
> do now is to create a new variable (group) if a certain condition in SIE 
> is met.
> I tried:
> 
> if (data2$SIE < 50.646){
> data2$group=as.factor("small")
> }
> which gives me "In if (data2$SIE < 50.646) { :  the condition has length 
>  > 1 and only the first element will be used"
> 
> and
> ifelse (data2$SIE < 50.64593, data2$group = 
> as.factor("small"),data2$group = as.factor("large"))
> with "Error: unexpected '=' in "ifelse (data2$SIE < 50.64593, 
> data2$group ="
> 
> I tried all other kinds of variations and so far, nothing!!

Do all of the following:

?"="
?"=="
?"if"
?ifelse

  -Peter Ehlers

> 
> Is there a good way to do this that someone could teach me?
> Thank you so much,
> Vitória
> 
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> 
>



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