The post is about R Packages in the form of Questions and Answers.

**Question:** What version of R do I run on my computer or laptop?

**Answer:** To get the information about the version of R, use the following command at the R prompt.

# get a version of R R.version.string

You will get a result like

[1] "R version 3.2.1 (2015-06-18)"

Note that a package in R language is a collection of objects that R Language can use. A package contains functions, data sets, and documentation (which helps how to use the package) or other objects such as dynamically loaded libraries of already compiled code.

### Installing R Packages

**Question:** How to check what packages are already installed?

**Answer:** To get a list of installed packages, write “library()” without quotation marks at the prompt. You will see the list of all of the packages installed in the local R directory of your computer system and then it will list all packages installed globally on your computer system.

# list all packages installed library( )

You would get results like (note that results below are given as an example only, it’s not a complete list)

in library ‘C:/Users/abcd/Documents/R/win-library/3.2’:

combinat Combinatorics utilities

proftools Output Processing Tools for R

rgl 3D visualization device system (OpenGL)

Packages in library ‘C:/Program Files/R/R-3.2.1/library’:*KernSmooth* Functions for kernel smoothing for Wand & Jones (1995)*MASS* Support Functions and Datasets for Venables and Ripley’s MASS*Matrix* Sparse and Dense Matrix Classes and Methods*methods* Formal Methods and Classes

mgcv Mixed GAM Computation Vehicle with Automatic Smoothness Estimation

Following is a very short list of packages installed in the local library.

Packages in library ‘C:/Users/imdad/Documents/R/win-library/3.5’:

*abind* Combine Multidimensional Arrays*AlgDesign* Algorithmic Experimental Design*askpass* Safe Password Entry for R, Git, and SSH*assertthat* Easy Pre and Post Assertions*tibble* Simple Data Frames*plyr* Tools for Splitting, Applying and Combining Data

R packages are essentially a combination of reusable code, documentation, and code that extend the power and capabilities of the R programming language. R packages are designed to be easily installed and used. The R packages are a major reason why R is so popular in data science. There are tens of thousands of R packages available on CRAN and other repositories, covering a wide range of tasks, from data manipulation and analysis to visualization and modeling.

For further details on R Packages, see the link Packages in R Language.