# Packages

R can be extended almost infinitely with packages: add-ons that folks have contributed that do specific things.

## How to find packages

Packages can be found in a variety of ways.

#### 1. The R project website

CRAN Lists all the packages,
as well as different collections that work on different subject areas.

#### 2. Articles

Many articles will cite the R packages they used.

#### 3. Google

Search for ‘R package’ and whatever task you are trying to accomplish.

#### 4. RStudio

RStudio has its’ own collection of packages: https://www.rstudio.com/products/rpackages/

#### 5. Various websites

Various websites maintain different collections of packages.

e.g., https://awesome-r.com/

## Installing packages

Packages can be installed from within RStudio, under the ‘packages’ pane.

Alternatively, you can install them with the `install.packages()`

function from within the console. Note the quotes.

## Loading packages

For every version of R, you only need to install a package once.

However, in each R session, you will need to load these packages using the `library()`

function. Note the lack of quotes.

## Recommended packages

### linear mixed effect models

General overview here

### Plotting tricks and hacks

- plotrix. Check the manual for all the cool things it can do!

### multivariate stats

Both these packages have good overviews and examples.

### spatial

## Other graphing packages

### ggplot2

ggplot2 is a powerful graphics language that translates models and data structure into graphics.

It can be complex to learn and use.

### lattice

Lattice improves on the default plotting options of base R, and
can be useful for multivariate data and multi-panel plots with data conditioned on other data.