R help - Jul 2008 - Row Sum, exclude positive values

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.

I believe it would look something like 

function(x)while x[FN + 1] != 0 && x[FN] != LN sum(x[FN] to x[FN + 1]);
FN FN + 1

But I cant seem to get the sintax right.
Could someone help me?
Cheers,
R

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Dear Rheannon,

Try

DF = c(4, 3, 2, 1, 0, -1, -2, -3, -2, 2, 1, -1, -2, -3, -2, -1, 1, 2)
sum(DF[DF<0])
[1] -17

HTH,

Jorge



On Tue, Jul 15, 2008 at 5:35 PM, Rheannon <rbrooks@uvic.ca> 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.
>
> I believe it would look something like
>
> function(x)while x[FN + 1] != 0 && x[FN] != LN sum(x[FN] to x[FN +
1]); FN
> > FN + 1
>
> But I cant seem to get the sintax right.
> Could someone help me?
> Cheers,
> R
>
> --
> View this message in context:
>
http://www.nabble.com/Row-Sum%2C-exclude-positive-values-tp18475407p18475407.html
> Sent from the R help mailing list archive at Nabble.com.
>
> ______________________________________________
> R-help@r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>
	[[alternative HTML version deleted]]

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