R help - May 2009 - rbind help

Hi

I have a dataset of orientation and elevation in a dataframe which I am
plotting in circular. Orientation is on the range 0-360, however I need to
reduce this to 0-180 as the values over 180 are not necessarily correct. I
can do

striae$orientation[striae$orientation>180]-180)

to extract these values, but I then want to combine them back in to the
original dataframe (with the elevation values). I assume rbind is the thing
to use and have tried something like:

test <- rbind((striae$orientation[striae$orientation>180]-180),
(striae$orientation[striae$orientation<=180]))

Not being a regular R user I suspect the syntax is easy when you know it!!
Any help much appreciated.

Best wishes

mike
-- 
View this message in context:
http://www.nabble.com/rbind-help-tp23499705p23499705.html
Sent from the R help mailing list archive at Nabble.com.

Hi Mike,

MikSmith wrote:
> Hi
> 
> I have a dataset of orientation and elevation in a dataframe which I am
> plotting in circular. Orientation is on the range 0-360, however I need to
> reduce this to 0-180 as the values over 180 are not necessarily correct. I
> can do
> 
> striae$orientation[striae$orientation>180]-180)
> 
> to extract these values, but I then want to combine them back in to the
> original dataframe (with the elevation values). I assume rbind is the thing
> to use and have tried something like:
> 
> test <- rbind((striae$orientation[striae$orientation>180]-180),
> (striae$orientation[striae$orientation<=180]))
I would do the conversion in place:

striae$orientation <- ifelse(striae$orientation > 108, 
striae$orientation - 180, striae$orientation)

Best,

Jim
> 
> Not being a regular R user I suspect the syntax is easy when you know it!!
> Any help much appreciated.
> 
> Best wishes
> 
> mike
-- 
James W. MacDonald, M.S.
Biostatistician
Douglas Lab
University of Michigan
Department of Human Genetics
5912 Buhl
1241 E. Catherine St.
Ann Arbor MI 48109-5618
734-615-7826