#### Computer Skills for Research

# Graphing with R

#### By Mark Ciotola

First published on October 10, 2019. Last updated on February 6, 2021.

## What is R?

“R is a language and environment for for statistical computing and graphics.”[1] In other words, R is primarily intended to perform statistical analysis. However, excellent plots can also be created in R.

R provides both a command line interface, as well as a graphical user interface (GUI). Admittedly, the GUI looks like a command line interface, but it contains several buttons that can save time.

## Obtaining R

R is freely available under the open source GNU license. Download R at the R Projectpage.

## Running R

A quick way to learn a few R basics is to create a simple plot.

To start with R, it is easiest to run it from the environment. Under the File menu (at the top of the screen), choose *New Document*. Save the document as R_simple_plot.

Add the following line at the “>” prompt. This will provide data for a plot. First we state the variable “population” to hold the data. We use the “<-” notation to assign data to that variable. “c()” is a function that you can use to provide data.

population <- c(1000, 1200, 1400, 1500 , 1550)

Then add the below line to tell R to create a plot of the data. Plot is a function. It processes information supplied to it between the parentheses. “Type” describes the format of the plot. “Col” specifies a color for the plot.

plot(population, type = "o", col="blue")

Save the file again. To view the plot, choose the “Source Script” button (the R circle button), then choose your file. You should see a plot similar to that below.

## A More Complicated Example

Below is a more complicated example. You can copy and paste it into a new file to see the result.

x <- 0:200 y <- exp( 0.05 * x ) par(mfrow=c(1,1)) plot(x, y, main=expression(paste("Pure Exponential Growth k = 0.50, ", y[0], " = 1")), xlab="Time", ylab="Quantity", type = "l") #abline(lm(y~x)) #abline(lowess(x,y)) #lines(lowess(x,y)) #lines(x, y, type="l") #title("Power Progression of Romanov Dynasty versus Year")

## Resources

- r-project(information how to get and use R)
- r-project,In Introduction to R(detailed)
- Frank McCown, Producing Simple Graphs with R(a reasonably good tutorial, if you know how to open up an r window)

« The Unix/Linux command line | COURSE | Creating a web page with HTML »