R help - Sep 2009 - How can I use R:sort function in C code?

Hi, I wrote a C extension for R. Within the C code I wanted to invoke the
R's sort function, with the argument "index.return = TRUE". I
found it is a
difficult problem, how can I do that? I have implemented the decreasing
sorting by the code "PROTECT(R_fcall = lang3(install("sort"), x,
desc));",
but how to define the "index.return" argument?

Thanks in advanced!

-- 
Guozhu. Wen
mail: guozhuwen@gmail.com
douban: http://www.douban.com/people/wentrue/
blog: http://www.wentrue.net/blog/
twitter: https://twitter.com/wentrue

	[[alternative HTML version deleted]]

Guozhu.Wen wrote:
> 
> Hi, I wrote a C extension for R. Within the C code I wanted to invoke the
> R's sort function, with the argument "index.return = TRUE". I
found it is
> a
> difficult problem, how can I do that? I have implemented the decreasing
> sorting by the code "PROTECT(R_fcall =
lang3(install("sort"), x, desc));",
> but how to define the "index.return" argument?
> 
> Thanks in advanced!
> 
> -- 
> Guozhu. Wen
> 
> 
I found this a little tricky to do the first time-- but it's not bad at all
once you go through it. The steps I usually follow are:

1. Create an object to hold your function call.

2. Find the R function you want to call.

3. Prepare the function call by setting attributes on your object.

4. Execute the function call.

5. Recover data.

Unfortunately, I have to run to a meeting this morning so I can't write out
examples of all these steps. I suggest looking at section 5.11 of the
"Writing R Extensions" manual. Also, section 10.2 of the tikzDevice
vignette
details an example of calling an R function from within a C function.

Good luck!

-Charlie

-----
Charlie Sharpsteen
Undergraduate
Environmental Resources Engineering
Humboldt State University
-- 
View this message in context:
http://www.nabble.com/How-can-I-use-R%3Asort-function-in-C-code--tp25450683p25455479.html
Sent from the R help mailing list archive at Nabble.com.