[Rd] bug of *switch* function

Peter Dalgaard P.Dalgaard at biostat.ku.dk
Mon Mar 9 15:21:32 CET 2009


guangchuang yu wrote:
> Hi,
> 
> When I call the *switch* function first time, it works. but when I call it
> at the second time, it does nothing. The version I use is R version 2.9.0
> Under development (unstable) (2009-02-21 r47969)
> 
> 
> here is the output:
> 
>> organism="human"
>>     species <- switch(organism,
>         human <- "Hs",
>         fly <- "Dm",
>         mouse <- "Mm",
>         rat <- "Rn",
>         yeast <- "Sc"
>     )
>  species <- switch(organism,
> +   human <- "Hs",
> +   fly <- "Dm",
> +   mouse <- "Mm",
> +   rat <- "Rn",
> +   yeast <- "Sc"
> +  )
>> species
> [1] "Hs"
>> organism="yeast"
>>     species <- switch(organism,
>         human <- "Hs",
>         fly <- "Dm",
>         mouse <- "Mm",
>         rat <- "Rn",
>         yeast <- "Sc"
>     )
>  species <- switch(organism,
> +   human <- "Hs",
> +   fly <- "Dm",
> +   mouse <- "Mm",
> +   rat <- "Rn",
> +   yeast <- "Sc"
> +  )
>> species
> [1] "Hs"
> 
> 
> when I change *organism* to "yeast", and call *switch* function again,
> *species* suppose to be changed to "Sc", but it remain it's original value.
> 
> You can see my screenshot at
> http://ygc.azpala.com/2009/03/09/bug-of-r-29-dev
> 

Wrong syntax. Check the examples of ?switch.

If the first argument to switch is not numeric, and does not match the
name of any named argument (of which you have none), then the result is
 the first unnamed argument (i.e. "Hs").

-- 
   O__  ---- Peter Dalgaard             Øster Farimagsgade 5, Entr.B
  c/ /'_ --- Dept. of Biostatistics     PO Box 2099, 1014 Cph. K
 (*) \(*) -- University of Copenhagen   Denmark      Ph:  (+45) 35327918
~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk)              FAX: (+45) 35327907



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