R function to return the license of a package?

问题:

I'd like to return the package license as declared in the DESCRIPTION file of an R package (ideally I'd rather have the URL that CRAN automatically adds to all the common licenses it recognizes).

I realize I can get the license R itself is distributed under with

license()

which amazingly doesn't apply to packages; e.g. license("packagename")

Nor is this data returned by a call to citation("packagename").

回答1:

you are looking for packageDescription

eg:

packageDescription("stats", fields="License")
[1] "Part of R 2.15.3"

packageDescription("ggplot2", fields="License")
[1] "GPL-2"

回答2:

If you want to get the licenses for all installed packages, then use the installed.packages command.

Borrowing from the help page for this command:

lisc <- installed.packages(fields = "License")

To output the licenses to a csv file:

write.csv(lisc[,c(1,10)], "RPackageLicenses.csv")