[R] Row Sum, exclude positive values

[Jim Lemon]

On Tue, 2008-07-15 at 14:35 -0700, Rheannon wrote:
> Hello,
> 
> I'd like to sum the values of a row from the first negative number (FN) to
> the last negative number (LN), but not add any positive values to the sum.
> Then apply this to each row of the data frame.
> 
> For example if I have a dataframe with Row 1 values 
> DF = (4, 3, 2, 1, 0, -1, -2, -3, -2, 2, 1, -1, -2, -3, -2, -1, 1, 2)
> I would like to sum the numbers from column 6 to column 16, but not include
> column 10 & 11.
> 
Hi Rheannon,

How about:

sum(DF[DF<0])

Jim