[R] factor -> numeric

[Spencer Graves]

      Have you tried "as.numeric(as.character(rsm2$Value))"?  The 
construct "as.numeric(rsm2$Value)" returns the NUMERIC CODES for the 
different levels;  "as.character(rsm2$Value)" returns the character 
representation, which you can then convert to numeric. 

      hope this helps.  spencer graves

Mikkel Grum wrote:

>Hi,
>
>I'm extracting data from a database with values for
>different observation types in the same variable
>(another variable deifnes the observation type).  Some
>of these observation types are factors, so R naturally
>classifies the entire variable as a factor.  I want to
>select a subset and convert the values to numeric
>values, but it isn't working; as shown below:
>
>  
>
>>rsm2<-subset(rsm,PlantStrataId==2,select=c(Value))
>>rsm2$Value
>>    
>>
>  [1]                               70 30             
>              15 50      
> [26]                2                                
>                         
> [51]                                                
>6                         
> [76]                                                 
>                 30    10
>[101]                                        17       
>              15         
>[126]   
>24 Levels:  0-25 1 10 12 13 15 17 2 20 23 25 25-50 3
>30 4 40 5 50 50-75 ... Present
>  
>
>>rsm2$Value<-as.numeric("rsm2$Value")
>>    
>>
>Warning message: 
>NAs introduced by coercion 
>  
>
>>rsm2$Value
>>    
>>
>  [1] NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA
>NA NA NA NA NA NA NA NA NA
> [26] NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA
>NA NA NA NA NA NA NA NA NA
> [51] NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA
>NA NA NA NA NA NA NA NA NA
> [76] NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA
>NA NA NA NA NA NA NA NA NA
>[101] NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA
>NA NA NA NA NA NA NA NA NA
>[126] NA
>  
>
>
>is there any way out?  Help much appreciated.
>
>cheers,
>Mikkel
>
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