[R] If condition using accessors

Peter Ehlers ehlers at ucalgary.ca
Fri Nov 27 14:03:27 CET 2009


Peter Ehlers wrote:
> 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

Actually, I assumed without checking that ?ifelse would
have an example of assignment of the result of the test.
(Maybe it could be added.)

yourVariable <- ifelse(...)

  -Peter Ehlers

> 
>>
>> Is there a good way to do this that someone could teach me?
>> Thank you so much,
>> Vitória
>>
>> ______________________________________________
>> R-help at r-project.org mailing list
>> https://stat.ethz.ch/mailman/listinfo/r-help
>> PLEASE do read the posting guide 
>> http://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.
>>
>>
> 
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide 
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
> 
>



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