[R] Data Manipulation

[Peter Dalgaard]

Peter Rote wrote:
> I still struggling with this:
> 
>  error massage:
> 
>>  by(AlexETF,AlexETF$Industry,function(a) {filename = paste("C:/ab/",gsub("
>> ","",a$Industry[1]),".txt",sep="")
> +         print(filename)
> + write.table(a[,3,drop=FALSE],quote=FALSE,col.names=FALSE,row.names=FALSE)    
> +     }
> +  )  
> 
> [1] "C:/ab/Accident&HealthInsurance.txt"
> Error in `[.data.frame`(a, , 3, drop = FALSE) :
>   undefined columns selected

The message says that you haven't got three columns in a, so try
inserting print(dim(a)). Perhaps what you showed earlier was rownames
plus two columns?

-- 
   O__  ---- Peter Dalgaard             Øster Farimagsgade 5, Entr.B
  c/ /'_ --- Dept. of Biostatistics     PO Box 2099, 1014 Cph. K
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