[R] factor levels > numeric values

Jeff Newmiller jdnewmil at dcn.davis.CA.us
Wed Nov 12 16:39:05 CET 2014


Another approach is to re-import your data using options that do not put the data into a factor in the first place.  For example you can use the colClasses parameter in the read.table family of functions to specify "numeric" for that column. If you need to give special handling to that column anyway (using strong functions) then you can use the stringsAsFactors=FALSE or as.is=TRUE parameter settings and avoid the as.character() band-aid in your code.
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On November 12, 2014 6:56:11 AM PST, David L Carlson <dcarlson at tamu.edu> wrote:
>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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>
>______________________________________________
>R-help at r-project.org mailing list
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>
>______________________________________________
>R-help at r-project.org mailing list
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>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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