[R] "Re: Change class factor to numeric"

Ivan Calandra ivan.calandra at uni-hamburg.de
Tue May 18 18:17:02 CEST 2010 

Hi again,

If you used the function read.table() to read from a csv file into a 
data.frame, it is weird that numeric data are converted into factors.
I would check in the original data that you don't have a typo somewhere. 
I don't know all the possibilities, but a special character can 
definitely make R interpret this variable differently.

For Drenaje, it is normal. In that case you can just use:
caperf$Drenaje <- factor(caperf$Drenaje)

HTH
Ivan

Le 5/18/2010 17:59, Arantzazu Blanco Bernardeau a écrit :
> Hello
> so, here you have the output of the data frame. The data frame comes from a csv file.
> I could take Gr_2 instead of arcilla, because it is the same value... but curiously, it is a factor as well.
>    
>> str(caperf)
>>      
> 'data.frame':    556 obs. of  38 variables:
>   $ Hoja        : int  818 818 818 818 818 818 818 818 818 818 ...
>   $ idmuestra   : Factor w/ 555 levels "1015-I","1015-II",..: 26 27 28 29 31 32 33 34 30 35 ...
>   $ Año         : int  1994 1994 1994 1994 1994 1994 1994 1994 1994 1994 ...
>   $ x           : int  655500 633050 632200 635000 637150 643700 655300 648000 653400 646200 ...
>   $ y           : int  4285800 4283050 4298150 4290000 4294800 4288850 4282700 4290350 4298450 4296650 ...
>   $ CO_gkg1     : num  3.7 6.5 6.3 2.6 12.1 6.9 3.5 10.8 10.3 3.3 ...
>   $ NTgkg_1     : num  0.53 1.01 0.66 0.42 1.3 0.82 0.43 1.31 0.85 0.51 ...
>   $ C_Nratio    : num  6.98 6.46 9.55 6.18 9.33 ...
>   $ C03Ca       : num  53.6 38 1.2 1.1 21.1 ...
>   $ pHw         : num  8 8.4 8.3 8.4 8.45 8.2 8.4 8.4 8.1 8.4 ...
>   $ pHClK       : num  7.5 7.4 7.2 7.4 8.3 7.5 7.8 7.4 7.4 7.5 ...
>   $ CCC         : num  9.7 14.4 10.5 7.2 12.8 ...
>   $ CEdSm       : num  0.62 0.72 0.38 0.36 19.35 ...
>   $ pF1_3atm    : num  25.4 21.3 9.1 12.8 24.1 ...
>   $ pF15atm     : num  15.3 10.6 5.8 6.1 8.45 11 3.7 18.8 10 14.3 ...
>   $ Gr_2        : Factor w/ 391 levels "0","0.71","0.9",..: 200 31 158 36 142 60 377 263 140 151 ...
>   $ Gr2_20      : num  19.1 39.1 2.9 5.2 NA 12.5 5.7 29.5 17.3 10.5 ...
>   $ Gr20_50     : num  17.6 9.8 4.7 4 NA 10.4 4.2 13.3 12.5 7.8 ...
>   $ Gr50_100    : num  14.1 12.2 7.6 9 NA 9.1 6.1 8.5 9.1 18.9 ...
>   $ Gr100_250   : num  13.4 17.1 28.7 46.2 NA 20.8 28.7 13.6 16.8 32.9 ...
>   $ Gr250_500   : num  7.1 5.7 28.8 15.2 NA 24.7 23.4 3.8 11.4 6.9 ...
>   $ Gr500_1000  : num  4 1.8 5 3.9 NA 4.2 14.3 0.9 8.9 2.1 ...
>   $ Gr1000_2000 : num  1.4 2 1.9 4 NA 4.1 8.9 0.4 4.8 0.9 ...
>   $ arcilla     : Factor w/ 391 levels "0","0.71","0.9",..: 201 32 158 37 NA 61 377 263 141 151 ...
>   $ limo        : num  36.7 48.9 7.6 9.2 0 22.9 9.9 42.8 29.8 18.3 ...
>   $ arena       : num  40 38.8 72 78.3 0 62.9 81.4 27.2 51 61.7 ...
>   $ SUMA        : Factor w/ 15 levels "0","100","100.2",..: 2 2 2 2 1 2 2 2 2 2 ...
>   $ codusosuelo : logi  NA NA NA NA NA NA ...
>   $ pendiente   : Factor w/ 9 levels "0","1","2","3",..: 3 2 3 3 2 4 3 2 2 3 ...
>   $ profutil    : logi  NA NA NA NA NA NA ...
>   $ profutil.1  : int  50 110 120 40 80 52 30 120 37 80 ...
>   $ pedregosidad: int  0 0 0 2 0 4 4 0 3 3 ...
>   $ Drenaje     : int  4 4 4 4 1 4 5 3 4 4 ...
>   $ codsuelo    : num  1.1 2.1 3.1 2.1 12.3 2.5 2.5 4.1 2.5 2.1 ...
>   $ textura     : logi  NA NA NA NA NA NA ...
>   $ m.original  : Factor w/ 7 levels "Calizas . dolomías y areniscas",..: 4 7 7 2 2 7 7 7 7 7 ...
>   $ GRUPOPPAL   : Factor w/ 13 levels "Arenosoles","Calcisoles",..: 11 2 3 2 12 2 2 4 2 2 ...
>   $ SUELO       : Factor w/ 40 levels "Arenosol calcárico",..: 30 3 8 3 36 7 7 10 7 3 ...
>
> In the other side, the variable Drenaje (drainage) that is factor mode, appears as integer.
> Thanks a lot!
>
>
> Arantzazu Blanco Bernardeau
> Dpto de Química Agrícola, Geología y Edafología
> Universidad de Murcia-Campus de Espinardo
>
>
>
>
>
>
>
>
>
> ----------------------------------------
>    
>> Date: Tue, 18 May 2010 17:49:54 +0200
>> From: ivan.calandra at uni-hamburg.de
>> To:
>> Subject: Re: [R] "Re: Change class factor to numeric"
>>
>> Hi,
>>
>> I think that providing the output from str(data array or whatever you
>> have) would help.
>> Because, for now, we don't have much idea of what you really have.
>> Moreover, some sample data is always welcomed (using the function dput
>> for example)
>>
>> Ivan
>>
>>
>> Le 5/18/2010 17:36, Arantzazu Blanco Bernardeau a écrit :
>>      
>>> sorry I had a mistake sending my question without a subject. I do resend again. Please excuse me.
>>>
>>>        
>>>> Hello
>>>> I have a data array with soil variables (caperf), in which the variable "clay" is factor (as I see entering str(caperf)) . I need to do a regression model, so I need to have arcilla (=clay) as a numeric variable. For that I have entered
>>>>
>>>> as.numeric(as.character(arcilla))
>>>>
>>>> and even entering
>>>> 'as.numeric(levels(arcilla))[arcilla]'the variable is resting as factor, and the linear model is not valid (for my purposes).
>>>> The decimal commas have been converted to decimal points, so I have no idea of what to do.
>>>> Thanks a lot
>>>>
>>>>
>>>> Arantzazu Blanco Bernardeau
>>>> Dpto de Química Agrícola, Geología y Edafología
>>>> Universidad de Murcia-Campus de Espinardo
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> _________________________________________________________________
>>>> Diseñar aplicaciones tiene premio. ¡Si eres desarrollador no esperes más!
>>>> http://www.imaginemobile.es
>>>>
>>>>          
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>>>        
>> --
>> Ivan CALANDRA
>> PhD Student
>> University of Hamburg
>> Biozentrum Grindel und Zoologisches Museum
>> Abt. Säugetiere
>> Martin-Luther-King-Platz 3
>> D-20146 Hamburg, GERMANY
>> +49(0)40 42838 6231
>> ivan.calandra at uni-hamburg.de
>>
>> **********
>> http://www.for771.uni-bonn.de
>> http://webapp5.rrz.uni-hamburg.de/mammals/eng/mitarbeiter.php
>>
>> ______________________________________________
>> 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.
>
>    

-- 
Ivan CALANDRA
PhD Student
University of Hamburg
Biozentrum Grindel und Zoologisches Museum
Abt. Säugetiere
Martin-Luther-King-Platz 3
D-20146 Hamburg, GERMANY
+49(0)40 42838 6231
ivan.calandra at uni-hamburg.de

**********
http://www.for771.uni-bonn.de
http://webapp5.rrz.uni-hamburg.de/mammals/eng/mitarbeiter.php

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