Possible to extract R packages installed from CRAN and Github, separately?

I have a lot of R packages installed from CRAN as well as GitHub, and I was wondering how I could extract only those packages installed from CRAN, or only those from GitHub?

installed.packages() does not list any variables that I could use, as far as I understand...

Solution

packages <- installed.packages()[,1]

packages.keep <- sapply(packages, function(x) {
                                     url <- packageDescription(x)$URL
                                     if (length(grep("github", x = url)) == 0) {
                                        return(FALSE)
                                     }
                                     else {
                                        return(TRUE)
                                     }
                                  })

packages[packages.keep]

> packages[packages.keep]
           curl      data.table             DBI        devtools           dplyr 
         "curl"    "data.table"           "DBI"      "devtools"         "dplyr" 
       evaluate        forecast         ggplot2           git2r       gridExtra 
     "evaluate"      "forecast"       "ggplot2"         "git2r"     "gridExtra" 
          Hmisc            httr           mailR         memoise            mime 
        "Hmisc"          "httr"         "mailR"       "memoise"          "mime" 
           plyr            R.oo         R.utils              R6            Rcpp 
         "plyr"          "R.oo"       "R.utils"            "R6"          "Rcpp" 
  RcppArmadillo        reshape2        roxygen2         RSQLite       rversions 
"RcppArmadillo"      "reshape2"      "roxygen2"       "RSQLite"     "rversions" 
         scales         whisker 
       "scales"       "whisker"

To verify this result, here is the URL information for the ggplot2 package:

URL: http://ggplot2.org, https://github.com/hadley/ggplot2

It is clear that this package in part originated from GitHub, and it should appear in the list. If you want to work with packages which did not come from GitHub, you can easily modify my code.