Re: [R] Change class factor to numeric

From: Christoph Lehmann <christoph.lehmann_at_gmx.ch>
Date: Fri 06 May 2005 - 23:44:28 EST

?as.factor states:

To "revert" a factor 'f' to its original

      numeric values, 'as.numeric(levels(f))[f]' is recommended and
      slightly more efficient than 'as.numeric(as.character(f))


christoph

Petr Pikal wrote:

> Hi
> 
> On 6 May 2005 at 8:51, Paulo Justiniano Ribeiro Jr wrote:
> 

>>as.numeric()
> 
> Not exactly correct.
> 
> as.numeric(as.character())
> 
> gives you what you probably want ,if "mass" is really factor ;)
> 
> see
> 
> str(mass)
> 
> Cheers
> Petr
> 
> 

>>
>>
>>On Fri, 6 May 2005, Smit, R. (Robin) (IenT) wrote:
>>
>>>I am attempting to develop a multiple regression model using
>>>selected model variables that should all be treated as numeric
>>>(mostly real) values. However, R considers one specific variable
>>>"mass" automatically to be of class "factor", probably because
>>>"mass" consists of integer values that are repeated. I now want to
>>>force R to treat "mass" as a numeric variable in the regression but
>>>am not sure how to do this.
>>>
>>>>class(mass) <- "numeric"
>>>does not help me.
>>>
>>>Could anyone advise me on this?
>>>
>>>Kind regards,
>>>Robin Smit
>>>
>>>
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>>><http://www.tno.nl/industrie_en_techniek/mobiliteit_en_(transport)/m
>>>ilie ustudies/environmental_studies_and/>
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>>>
>>Paulo Justiniano Ribeiro Jr
>>LEG (Laboratório de Estatística e Geoinformação)
>>Departamento de Estatística
>>Universidade Federal do Paraná
>>Caixa Postal 19.081
>>CEP 81.531-990
>>Curitiba, PR - Brasil
>>Tel: (+55) 41 361 3573
>>Fax: (+55) 41 361 3141
>>e-mail: paulojus@est.ufpr.br
>>http://www.est.ufpr.br/~paulojus
>>
>>______________________________________________
>>R-help@stat.math.ethz.ch mailing list
>>https://stat.ethz.ch/mailman/listinfo/r-help
>>PLEASE do read the posting guide!
>>http://www.R-project.org/posting-guide.html
> 
> Petr Pikal
> petr.pikal@precheza.cz
> 
> ______________________________________________
> R-help@stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
> 
>

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R-help@stat.math.ethz.ch mailing list
https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Fri May 06 22:35:57 2005

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