[R] question about subset

[Sean Davis]

On May 5, 2005, at 6:31 PM, jose silva wrote:

> rois there any way to get a subset of a data frame with the ordered 
> indexes or without these indexes?
>
> example:
>
> mydata<- data.frame(A=seq(1,10), B=c(-5,2,-4,6,-8,-9,2,5,7,0))
> subset(mydata, B>0)
>   A B
> 2 2 2
> 4 4 6
> 7 7 2
> 8 8 5
> 9 9 7
>
> I would like to obtain this:
>
>   A B
> 1 2 2
> 2 4 6
> 3 7 2
> 4 8 5
> 5 9 7
>

 > x <- subset(mydata, B>0)
 > row.names(x) <- rank(x$A)
 > x
   A B
1 2 2
2 4 6
3 7 2
4 8 5
5 9 7

> or this
>
>   A B
>   2 2
>   4 6
>   7 2
>   8 5
>   9 7
>

I think you already got this using subset.  The row.names can be used 
to set the row names to whatever you want.

Sean