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Chapter title description
Chapter 1
Intro to basics
Take your first steps with R. In this chapter, you will learn how to use the console as a calculator and how to assign variables. You will also get to know the basic data types in R. Let's get started.

🔧 this my solutions to Intro to basics

How it works

In the editor on the right you should type R code to solve the exercises. When you hit the 'Submit Answer' button, every line of code is interpreted and executed by R and you get a message whether or not your code was correct. The output of your R code is shown in the console in the lower right corner.

R makes use of the # sign to add comments, so that you and others can understand what the R code is about. Just like Twitter! Comments are not run as R code, so they will not influence your result. For example, Calculate 3 + 4 in the editor on the right is a comment.

You can also execute R commands straight in the console. This is a good way to experiment with R code, as your submission is not checked for correctness.

🔨 sol :

# Calculate 3 + 4
3 + 4

# Calculate 6 + 12
6+12

Arithmetic with R

In its most basic form, R can be used as a simple calculator. Consider the following arithmetic operators:

  • Addition: +

  • Subtraction: -

  • Multiplication: *

  • Division: /

  • Exponentiation: ^

  • Modulo: %% The last two might need some explaining:

  • The ^ operator raises the number to its left to the power of the number to its right: for example 3^2 is 9.

  • The modulo returns the remainder of the division of the number to the left by the number on its right, for example 5 modulo 3 or 5 %% 3 is 2.

With this knowledge, follow the instructions to complete the exercise.

🔨 sol :

# An addition
5 + 5 

# A subtraction
5 - 5 

# A multiplication
3 * 5

 # A division
(5 + 5) / 2 

# Exponentiation
2^5


# Modulo
28^6

Variable assignment

A basic concept in (statistical) programming is called a variable.

A variable allows you to store a value (e.g. 4) or an object (e.g. a function description) in R. You can then later use this variable's name to easily access the value or the object that is stored within this variable.

You can assign a value 4 to a variable my_var with the command

my_var <- 4

🔨 sol :

# Assign the value 42 to x
x <- 42

# Print out the value of the variable x
x

Variable assignment (2)

Suppose you have a fruit basket with five apples. As a data analyst in training, you want to store the number of apples in a variable with the name my_apples.

🔨 sol :

# Assign the value 5 to the variable my_apples

my_apples <- 5
# Print out the value of the variable my_apples
my_apples

Variable assignment (3)

Every tasty fruit basket needs oranges, so you decide to add six oranges. As a data analyst, your reflex is to immediately create the variable my_oranges and assign the value 6 to it. Next, you want to calculate how many pieces of fruit you have in total. Since you have given meaningful names to these values, you can now code this in a clear way:

my_apples + my_oranges

🔨 sol:

# Assign a value to the variables my_apples and my_oranges
my_apples <- 5

my_oranges <- 6
# Add these two variables together

my_apples + my_oranges
# Create the variable my_fruit
my_fruit =my_apples + my_oranges

Apples and oranges

Common knowledge tells you not to add apples and oranges. But hey, that is what you just did, no :-)? The my_apples and my_oranges variables both contained a number in the previous exercise.
The + operator works with numeric variables in R. If you really tried to add "apples" and "oranges", and assigned a text value to the variable my_oranges (see the editor), you would be trying to assign the addition of a numeric and a character variable to the variable my_fruit.
This is not possible.

🔨 sol :

# Assign a value to the variable my_apples
my_apples <- 5 

# Fix the assignment of my_oranges
my_oranges <- 6

# Create the variable my_fruit and print it out
my_fruit <- my_apples + my_oranges 
my_fruit

Basic data types in R

R works with numerous data types. Some of the most basic types to get started are:

  • Decimal values like 4.5 are called numerics.
  • Whole numbers like 4 are called integers. Integers are also numerics.
  • Boolean values (TRUE or FALSE) are called logical.
  • Text (or string) values are called characters. Note how the quotation marks in the editor indicate that "some text" is a string.

🔨 sol :

# Change my_numeric to be 42
my_numeric <- 42

# Change my_character to be "universe"
my_character <- "universe"

# Change my_logical to be FALSE
my_logical <- FALSE

What's that data type?

Do you remember that when you added 5 + "six" , you got an error due to a mismatch in data types? You can avoid such embarrassing situations by checking the data type of a variable beforehand.
You can do this with the class() function, as the code in the editor shows.

🔨 sol :

# Declare variables of different types
my_numeric <- 42
my_character <- "universe"
my_logical <- FALSE 

# Check class of my_numeric
class(my_numeric)


# Check class of my_character
class(my_character)

# Check class of my_logical
class(my_logical)