Welcome to R! - Basics of R Programming

1. Getting started with R

RStudio is one of the most popular environment for R programming. Download and install it from http://www.rstudio.com/download.

When you open RStudio, you will be seeing the console screen, which would look like:

We will be typing the codes in the line with >, and you will get an output after [#], where # is the number that specifies the order of the code. For example:

1+1

## [1] 2

This [1] means that this is the first code that it was written.

This will not save the code that you wrote, so you can alternatively open a new R script, and type the codes there. To run the code, go to the line and press Ctrl + Enter. TYou can alternatively, press the Run button at the top right side of the screen. You will then see the output in the console screen.

As a beginning, we will cover the basics of math operations.

2. Math operations

R can do all math operations:

Operation	Meaning
+	Addition
-	Subtraction
*	Multiplication
/	Division

For example:

1 + 2

## [1] 3

2 * 4

## [1] 8

1 - 4

## [1] -3

6 / 2

## [1] 3

3. Objects

Objects are very important in R programming. You can assign a value to the object by using <-. For example,

a <- 1

The code above substitutes 1 into an object a.

## [1] 1

We can do all operations with objects. For example:

a <- 5
a * 2

## [1] 10

day1 <- 10
day2 <- 4

day1 + day2

## [1] 14

4. Comments

We can add comments in R codes by using #. R won’t recognize all the things that you wrote afterwards, so you can add some explanations to the code through comments. For example:

hour <- 5 # Number of hours
minute <- 5 * 60 # Number of minutes

minute # Get the output inside the minute object

## [1] 300

Throughout this R lab, I will be adding some explanations inside the code by using comments.

5. Print statement

We can use

print()

to print out the object inside (). FOr example:

number <- 1
print(number)

## [1] 1

However, we can also return the output of the object without print(), and it is often omitted in programming:

number <- 1
# Write number object without print()
number

## [1] 1