Introduction to R objects

In this document, we will learn how to define “objects” in R.

Defining objects

Let’s assign the value 1 to an object called x

# assign the value 1 to the variable x
x <- 1 

We can view the value of x by writing it’s name in a code chunk:

# view x
x

[1] 1

Another way to assign a value to a variable is using “=”

# assign the value of 3 to the variable y using =
y = 3

# view y
y 

[1] 3

You can also assign the output of mathematical calculations to a variable

# assign the output of 1 + 1 to the variable z
z <- 1 + 1
# view z
z

[1] 2

Exercise

As an exercise, your task is to define a new object w that contains the output of the product of 5 and 2.

1. Create a new code chunk

2. Define the variable w, assign to it the output of the product of 5 and 2

3. View the output of the object in the console.

Solution to exercise

w <- 5 * 2
w

[1] 10

Working with variables

Let’s do some computations with our variables

# Define result to be the product of z and 7
result <- z * 7
result

[1] 14

# update the value of z to be 4^2
z <- 4^2

Question: Do you think result will have changed?

Look at the values of result and z:

result

[1] 14

z

[1] 16

Exercise

What will the output of the following code chunk be:

value <- 1
computed_result <- value * 10 + 3^2
value <- value + 2
computed_result * 2 

[1] 38

Variable names

Which of the following are valid R variable names?

min_height
max.height
_age
.mass
MaxLength
min-length
2widths
celsius2kelvin

The generally recommended variable name convention is: variable_name