[R] How to build a vignette?

[PO SU]

Dear expeRts,
  I know we can build a vignette from .Rmd file, but  i find a lot of r packages have R topic documented words then followed an index, then functions'document which are already described in .RD files. I mean that , i don't want to write a vignette , but rather using function documents from .Rd files, how can i do?
 TKS.
 




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PO SU
mail: desolator88 at 163.com 
Majored in Statistics from SJTU