[R] Create data frame from header only

[Henrik Bengtsson]

See dataFrame() in R.utils.  It was design for the purpose of
allocating empty data frames in an efficient way.

Example:

> library(R.utils);
> df <- dataFrame(colClasses=c(a="integer", b="double"), nrow=10);
> str(df)
'data.frame':   10 obs. of  2 variables:
 $ a: int  0 0 0 0 0 0 0 0 0 0
 $ b: num  0 0 0 0 0 0 0 0 0 0

/Henrik


On Mon, Aug 4, 2008 at 6:42 PM, Etienne B. Racine <etiennebr at gmail.com> wrote:
>
> Even if it's not so elegant, I will bind it in a function, so I don't have to
> bother with that anymore. I think there should be a simple function in R to
> initialize an empty data frame. From what I've read, it is a recurrent
> question on that list.
>
> #Create an empty data frame from a header list
> empty.df<- function(header){
>        df<-data.frame(matrix(matrix(rep(1,length(header)),1),1))
>        colnames(df)<-header
>        return(df[NULL,])
> }
>
> # Usage
> new.df <- empty.df(paste("A",1:5,sep=""))
>> new.df
> [1] A1 A2 A3 A4 A5
> <0 rows> (or 0-length row.names)
>
> Thanks again,
> Etienne
>
>
> milton ruser wrote:
>>
>> Hi Etienne
>>
>> It is not so elegant, bu I think that work.
>>
>>
>> colname.list<-paste("A",1:5,sep="")
>>
>> df<-data.frame(matrix(matrix(rep(1,length(colname.list)),1),1))
>> df
>> colnames(df)<-colname.list
>> df
>>
>> df<-df[-1,]
>> df
>>
>> Cheers,
>>
>>
>> Miltinho Astronauta
>> Brazil
>>
>
> --
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