R – 警告:无法访问存储库的索引

这是我的操作系统细节:

$ uname -a Linux starbuck 3.2.0-92-generic #131-Ubuntu SMP Tue Oct 20 16:16:02 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux 

这是我的R版本:

 $ R --version R version 3.2.2 (2015-08-14) -- "Fire Safety" 

这是我的.Rprofile

 options("repos" = c(CRAN = "https://cran.r-project.org")) 

现在当我打开R并尝试列出可用的软件包时:

  > available.packages() Warning: unable to access index for repository https://cran.r-project.org/src/contrib Package Version Priority Depends Imports LinkingTo Suggests Enhances License License_is_FOSS License_restricts_use OS_type Archs MD5sum NeedsCompilation File Repository