[R] Factor Madness

Johannes Graumann johannes_graumann at web.de
Wed Dec 19 11:48:30 CET 2007


Yep, but I figured that out quite fast ;0)
Thanks for giving me a hand ... you want believe a many times I skimmed the
cbind help without actually seeing this ... well, it was 0:30 ...

Thanks again, Joh

Tony Plate wrote:

> Whoops, it looks like there's a typo in ?cbind (R version 2.6.0 Patched
> (2007-10-11 r43143)), and I blindly copied it into my message.
> 
> That should read (emphasis added):
> 
> "and convert character columns to factors unless stringsAsFactors =
> ***FALSE***"
> 
> Here's an example:
> 
>  > x <- data.frame(X=1:3)
>  > sapply(cbind(x, letters[1:3]), class)
>             X letters[1:3]
>     "integer"     "factor"
>  > sapply(cbind(x, letters[1:3], stringsAsFactors=FALSE), class)
>             X letters[1:3]
>     "integer"  "character"
>  >
> 
> Thanks to Mark Leeds for pointing that out to me in a private message!
> 
> (I see this still in the source at
> https://svn.r-project.org/R/trunk/src/library/base/man/cbind.Rd -- is that
> the right place to look for the latest source to make sure it hasn't been
> fixed already?)
> 
> -- Tony Plate
> 
> 
> Tony Plate wrote:
>>  From ?cbind:
>> 
>> Data frame methods
>> The cbind data frame method is just a wrapper for data.frame(...,
>> check.names = FALSE). This means that it will split matrix columns in
>> data frame arguments, and convert character columns to factors unless
>> stringsAsFactors = TRUE is passed.
>> 
>> (I'm guessing 'spectrum' is a data.frame before the code fragment you've
>> shown)
>> 
>> hope this helps,
>> 
>> Tony Plate
>> 
>> Johannes Graumann wrote:
>>> Why is class(spectrum[["Ion"]]) after this "factor"?
>>>
>>> spectrum <- cbind(spectrum,Ion=rep("",
>>> nrow(spectrum)),Deviation.AMU=rep(0.0, nrow(spectrum)))
>>>
>>> slowly going crazy ...
>>>
>>> Joh
>>>
>>> ______________________________________________
>>> 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.
>>
> 
> ______________________________________________
> 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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