[R] factor levels > numeric values

Ivan Calandra ivan.calandra at univ-reims.fr
Wed Nov 12 16:20:12 CET 2014


I have not completely followed the discussion, so excuse me if it was 
already pointed out.
If numeric data are read as factors, this means that there are not only 
numeric data in the column. It could be an empty space somewhere, or 
some character that should be NA, or...
I think it is worth spending some time searching for the typo so that 
the file will be read correctly in R.

HTH,
Ivan

--
Ivan Calandra, ATER
University of Reims Champagne-Ardenne
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Le 12/11/14 15:56, David L Carlson a écrit :
> Also look at the Frequently Asked Questions document that comes with your R installation:
>
> 7.10 How do I convert factors to numeric?
>
> It may happen that when reading numeric data into R (usually, when reading in a file), they come in as factors. If f is such a factor object, you can use
>
> as.numeric(as.character(f))
>
> to get the numbers back. More efficient, but harder to remember, is
>
> as.numeric(levels(f))[as.integer(f)]
>
> In any case, do not call as.numeric() or their likes directly for the task at hand (as as.numeric() or unclass() give the internal codes).
>
> -------------------------------------
> David L Carlson
> Department of Anthropology
> Texas A&M University
> College Station, TX 77840-4352
>
> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org] On Behalf Of Gerrit Eichner
> Sent: Wednesday, November 12, 2014 8:06 AM
> To: David Studer
> Cc: r-help at r-project.org
> Subject: Re: [R] factor levels > numeric values
>
> Hello, David,
>
> take a look at the beginning of the "Warning" section of ?factor.
>
>    Hth  --  Gerrit
>
>> Hi everybody,
>>
>> I have another question (to which I could not find an answer in my r-books.
>> I am sure, it's not a great issue, but I simply lack of a good idea how to
>> solve this:
>>
>> One of my variables gets imported as a factor instead of a numeric variable.
>> Now I have a...
>> Factor w/ 63 levels "0","0.02","0.03",..: 1 NA NA 1 NA NA 1 1 53 10 ...
>>
>> How can I transform these factor levels into actual values?
>>
>> Thank you very much for any help!
>> David
>>
>> 	[[alternative HTML version deleted]]
>>
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> ______________________________________________
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> 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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