[Rd] A patch for do_sample: check replace arg

[Robert Gentleman]

should be there now

Seth Falcon wrote:
> A colleague sent me the following:
> 
>     If you specify probabilities in the 'sample' function and forget
>     to type 'prob=...', then you get nonsense. E.g.
>     
>         sample(1:10,1,c(0,0,0,0,1,0,0,0,0,0)) 
> 
>     does not filter '5', while 
>     
>         sample(1:10,1,prob=c(0,0,0,0,1,0,0,0,0,0)) 
> 
>     does it correctly.  I wish this would return an error because the
>     'replace' argument should only take logical args. Anyway, it is
>     easy to make this mistake and having it produce an error would be
>     nice.
> 
> Assuming there is not a use-case for specifying a logical vector for
> the 'replace' argument, I like the idea of raising an error if replace
> is not length one.  The following patch provides an implementation.
> 
> + seth
> 
> 
> Diff is against svn Revision: 37141
> --- a/src/main/random.c Sat Jan 21 10:54:11 2006 -0800
> +++ b/src/main/random.c Sat Jan 21 11:17:20 2006 -0800
> @@ -453,15 +453,18 @@
>  /* with/without replacement according to r. */
>  SEXP attribute_hidden do_sample(SEXP call, SEXP op, SEXP args, SEXP rho)
>  {
> -    SEXP x, y, prob;
> +    SEXP x, y, prob, sreplace;
>      int k, n, replace;
>      double *p;
>  
>      checkArity(op, args);
>      n = asInteger(CAR(args)); args = CDR(args);
>      k = asInteger(CAR(args)); args = CDR(args);
> -    replace = asLogical(CAR(args)); args = CDR(args);
> +    sreplace = CAR(args); args = CDR(args);
>      prob = CAR(args);
> +    if (length(sreplace) != 1)
> +        errorcall(call, _("invalid '%s' argument"), "replace");
> +    replace = asLogical(sreplace);
>      if (replace == NA_LOGICAL)
>         errorcall(call, _("invalid '%s' argument"), "replace");
>      if (n == NA_INTEGER || n < 1)
> 
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> 

-- 
Robert Gentleman, PhD
Program in Computational Biology
Division of Public Health Sciences
Fred Hutchinson Cancer Research Center
1100 Fairview Ave. N, M2-B876
PO Box 19024
Seattle, Washington 98109-1024
206-667-7700
rgentlem at fhcrc.org