[R] Select only cases with negative values

[Michael Just]

Hello,
I was wondering if there was a way to only select cases my from data
frame that contained a negative value?

> c<-c(1,2,3,4,5,6,7,8,9,10)
> d<- c(-1,2,-3,-4,5,6,-7,8,-9,10)
> f <- cbind(c,d)
> dat <-data.frame(f)
> dat.lm <-lm(c~d)

If I wanted to only use the rows that had a negative value in column d
for my regression, how could I make that selection?

Thanks,
Michael Just