List of user-installed R packages and their versions

This R command lists all the packages installed by the user (ignoring packages that come with R such as base and foreign) and the package versions.

ip <- as.data.frame(installed.packages()[,c(1,3:4)])
rownames(ip) <- NULL
ip <- ip[is.na(ip$Priority),1:2,drop=FALSE]
print(ip, row.names=FALSE)

Example output

       Package   Version
        bitops     1.0-6
 BradleyTerry2     1.0-6
          brew     1.0-6
         brglm     0.5-9
           car    2.0-25
         caret    6.0-47
          coin    1.0-24
    colorspace     1.2-6
        crayon     1.2.1
      devtools     1.8.0
     dichromat     2.0-0
        digest     0.6.8
         earth     4.4.0
      evaluate       0.7
[..snip..]

Tested with R 3.2.0.

This is a small step towards managing package versions: for a better solution, see the checkpoint package. You could also use the first column to reinstall user-installed R packages after an R upgrade.