List and description of all packages in CRAN from within R

r

Solution

Edit of an almost ten-year old accepted answer. What you likely want is not to scrape (unless you want to practice scraping) but use an existing interface: `tools::CRAN_package_db()`. Example:

> db <- tools::CRAN_package_db()[, c("Package", "Description")]
> dim(db)
[1] 18978     2
>

The function brings (currently) 66 columns back of which the of interest here are a part.

I actually think you want "Package" and "Title" as the "Description" can run to several lines. So here is the former, just put "Description" in the final subset if you really want "Description":

R> ## from http://developer.r-project.org/CRAN/Scripts/depends.R and adapted
R>
R> require("tools")
R>
R> getPackagesWithTitle <- function() {
+     contrib.url(getOption("repos")["CRAN"], "source") 
+     description <- sprintf("%s/web/packages/packages.rds", 
+                            getOption("repos")["CRAN"])
+     con <- if(substring(description, 1L, 7L) == "file://") {
+         file(description, "rb")
+     } else {
+         url(description, "rb")
+     }
+     on.exit(close(con))
+     db <- readRDS(gzcon(con))
+     rownames(db) <- NULL
+
+     db[, c("Package", "Title")]
+ }
R>
R>
R> head(getPackagesWithTitle())               # I shortened one Title here...
     Package              Title
[1,] "abc"                "Tools for Approximate Bayesian Computation (ABC)"
[2,] "abcdeFBA"           "ABCDE_FBA: A-Biologist-Can-Do-Everything of Flux ..."
[3,] "abd"                "The Analysis of Biological Data"
[4,] "abind"              "Combine multi-dimensional arrays"
[5,] "abn"                "Data Modelling with Additive Bayesian Networks"
[6,] "AcceptanceSampling" "Creation and evaluation of Acceptance Sampling Plans"
R>

Problem

I can get a list of all the available packages with the function: ``` ap <- available.packages() ``` But how can I also get a description of these packages from within R, so I can have a `data.frame` with two columns: package and description?

Original source