[R] A question about embedded R

[Peter Dalgaard]

Song Baiyi <song.baiyi at udo.edu> writes:

>     for(i = 0; i < n ; i++)
>         val = (double)REAL(eval(VECTOR_ELT(e,i), R_GlobalEnv))[0];
...
> eval_R_command("mean(1:5)")
> it worked fine and got 3,
> 
> but
> 
> eval_R_command("sum(1:5)")
> it produced a strange number 7.41098e-323! not 15
> 
> What is the problem?

You have a sum of integers, so the result is integer and you access it
as a REAL. You need explicit coercion, or to use
eval_R_command("as.double(sum(1:5))") 

-- 
   O__  ---- Peter Dalgaard             Blegdamsvej 3  
  c/ /'_ --- Dept. of Biostatistics     2200 Cph. N   
 (*) \(*) -- University of Copenhagen   Denmark      Ph: (+45) 35327918
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