# R Packages

R provides a good collection of functions for solving many developmental problems. These collections are called packages. Some packages are installed by default with R installation. Most of the packages are available on R official website http://CRAN.R-project.org/ , that we can easily install later as per our requirement .

## Get list of all installed packages

The library() function displays all the installed packages in your system.

`library()`

The above command displays the following results and this may vary depending on the settings of your pc.

```
Packages in library 'C:/Program Files/R/R-3.5.1/library':
base The R Base Package
boot Bootstrap Functions (Originally by Angelo Canty
for S)
class Functions for Classification
cluster "Finding Groups in Data": Cluster Analysis
Extended Rousseeuw et al.
codetools Code Analysis Tools for R
compiler The R Compiler Package
datasets The R Datasets Package
foreign Read Data Stored by 'Minitab', 'S', 'SAS',
'SPSS', 'Stata', 'Systat', 'Weka', 'dBase', ...
graphics The R Graphics Package
grDevices The R Graphics Devices and Support for Colours
and Fonts
grid The Grid Graphics Package
jsonlite A Robust, High Performance JSON Parser and
Generator for R
KernSmooth Functions for Kernel Smoothing Supporting Wand
& Jones (1995)
lattice Trellis Graphics for R
MASS Support Functions and Datasets for Venables and
Ripleys MASS
Matrix Sparse and Dense Matrix Classes and Methods
methods Formal Methods and Classes
mgcv Mixed GAM Computation Vehicle with Automatic
Smoothness Estimation
mime Map Filenames to MIME Types
mongolite Fast and Simple 'MongoDB' Client for R
nlme Linear and Nonlinear Mixed Effects Models
nnet Feed-Forward Neural Networks and Multinomial
Log-Linear Models
openssl Toolkit for Encryption, Signatures and
Certificates Based on OpenSSL
parallel Support for Parallel computation in R
rJava Low-Level R to Java Interface
rpart Recursive Partitioning and Regression Trees
spatial Functions for Kriging and Point Pattern
Analysis
splines Regression Spline Functions and Classes
stats The R Stats Package
stats4 Statistical Functions using S4 Classes
survival Survival Analysis
tcltk Tcl/Tk Interface
tools Tools for Package Development
translations The R Translations Package
utils The R Utils Package
xlsx Read, Write, Format Excel 2007 and Excel
97/2000/XP/2003 Files
xlsxjars Package required POI jars for the xlsx package
XML Tools for Parsing and Generating XML Within R
and S-Plus
```

## Load an installed package

The library() function is also used while loading an installed package.

`library(package_name)`

## Get Library Path

R provides libPaths() function to know the library paths in your system.

`.libPaths()`

## Change Library Path

If you want to change the library path, first makes it blank and then assign the desirable path in it. Suppose, we want to make the library installation path to 'C:/Program Files/R/R-3.5.1/library'.

```
.libPaths('')
.libPaths('C:/Program Files/R/R-3.5.1/library')
```

## Install a package from CRAN

To install a package from CRAN web page, follows the following syntax.

`install.packages("package_name")`

At the time of package installation, make sure to open R prompt as Administrator. So that you have right privileges to install the package.

## Install a downloaded package

To install a downloaded package, follows the following syntax.

`install.packages("full source path", repos = NULL, type = "source")`

## Uninstall a package

To uninstall a package, follows the following syntax.

`remove.packages(pkg, lib)`

Here, pkg is the name of the package to remove and lib is the library directory to remove.

**Example**

`remove.packages('rJava', 'C:/Program Files/R/R-3.5.1/library')`