Hadley Wickham [aut],
  Jim Hester [aut, cre],
  RStudio [cph]

Tools for Splitting, Applying and Combining Data

A set of tools that solves a common set of problems: you
    need to break a big problem down into manageable pieces, operate on each
    piece and then put all the pieces back together.  For example, you might
    want to fit a model to each spatial location or time point in your study,
    summarise data by panels or collapse high-dimensional arrays to simpler
    summary statistics. The development of 'plyr' has been generously supported
    by 'Becton Dickinson'.

person("Hadley", "Wickham", , "hadley@rstudio.com", c("aut", "cre"))

abind, testthat, tcltk, foreach, doParallel, itertools,
iterators, covr

A rewrite of the graphics layout capabilities, plus some
  support for interaction.

Support for parallel computation, including by forking
   (taken from package multicore), by sockets (taken from package snow)
   and random-number generation.

Abstractions for Promise-Based Asynchronous Programming

c(
      person("Joe", "Cheng", email = "joe@rstudio.com", role = c("aut", "cre")),
      person("RStudio", role = c("cph", "fnd"))
    )

Provides fundamental abstractions for doing asynchronous programming
    in R using promises. Asynchronous programming is useful for allowing a single
    R process to orchestrate multiple tasks in the background while also attending
    to something else. Semantics are similar to 'JavaScript' promises, but with a
    syntax that is idiomatic R.

Joe Cheng [aut, cre],
  RStudio [cph, fnd]

Tools for Working with Categorical Variables (Factors)

c(
    person("Hadley", "Wickham", , "hadley@rstudio.com", role = c("aut", "cre")),
    person("RStudio", role = c("cph", "fnd"))
  )

Helpers for reordering factor levels (including moving
    specified levels to front, ordering by first appearance, reversing, and
    randomly shuffling), and tools for modifying factor levels (including
    collapsing rare levels into other, 'anonymising', and manually 'recoding').