[Rcpp-devel] Returning an element from a List with its attributes?

Dear Wush and others,
Just to followup and say I've used this idea here:
https://github.com/talgalili/dendextendRcpp/blob/master/src/cut_lower.cpp

In general, it would have been better for me, where it possible to do some
(or all) of the things below:
1) Get the length of a List
2) Change the attribute of elements within a list
3) Have this not happen:

require(Rcpp)
cppFunction('
            SEXP temp(List x){
            return(x);
            }
            ')
x = list(structure(1L, animal = "cat"))
temp(x)
temp(x[[1]]) # I wish this didn't happen

(I'm possibly missing out things, but I thought of listing it just in case)


Many thanks for the help!
Tal






----------------Contact
Details:-------------------------------------------------------
Contact me: Tal.Galili at gmail.com |
Read me: www.talgalili.com (Hebrew) | www.biostatistics.co.il (Hebrew) |
www.r-statistics.com (English)

----------------------------------------------------------------------------------------------



On Tue, Aug 20, 2013 at 12:25 PM, Tal Galili <tal.galili at gmail.com> wrote:

Hello Wush,
Indeed, thank you!

I will write more on this after I finish the code, since there are some
bits which are a mystery to me.

Tal


----------------Contact
Details:-------------------------------------------------------
Contact me: Tal.Galili at gmail.com |
Read me: www.talgalili.com (Hebrew) | www.biostatistics.co.il (Hebrew) |
www.r-statistics.com (English)

----------------------------------------------------------------------------------------------



On Tue, Aug 20, 2013 at 12:13 PM, Wush Wu <wush978 at gmail.com> wrote:

Hi Tal,

```
cppFunction('
std::vector<RObject>  temp2_fail(RObject x){
   std::vector<RObject> lower;
   List x_list(wrap(x));
   int n = x_list.size();
   lower.push_back(x);
   return(lower) ;
}
            ')
```

Is this what you want?


2013/8/20 Tal Galili <tal.galili at gmail.com>

Dear list members,

I would like to be able to get an element pushed with its attributes,
and I came across the following problem:

cppFunction('
std::vector<List>  temp(List x){
   std::vector<List> lower;
   lower.push_back(x);
   return(lower) ;
}
            ')
x = list(structure(1L, animal = "cat"))
temp(x)
temp(x[1])
temp(x[[1]]) # is there a way to not make this output without
attributes?



If I use RObject, it will solve it, but then I would later not be able
to iterate over the object, because I can't seem to get the .size() of an
RObject.

Here is the code with the RObject:


cppFunction('
std::vector<RObject>  temp2(RObject x){
   std::vector<RObject> lower;
   lower.push_back(x);
   return(lower) ;
}
            ')
x = list(structure(1L, animal = "cat"))
temp2(x)
temp2(x[1])
temp2(x[[1]]) # Now it works as I want, but the following wouldn't work:




cppFunction('
std::vector<RObject>  temp2_fail(RObject x){
   std::vector<RObject> lower;
   int n x.size();
   lower.push_back(x);
   return(lower) ;
}
            ')



Any ideas?




----------------Contact
Details:-------------------------------------------------------
Contact me: Tal.Galili at gmail.com |
Read me: www.talgalili.com (Hebrew) | www.biostatistics.co.il (Hebrew)
| www.r-statistics.com (English)

----------------------------------------------------------------------------------------------