Basic data types

In R we have several built-in basic data types. The most common types of data that you will find are numbers, characters and booleans.

Key points

R is dynamically typed, meaning you don’t need to declare the type of a variable explicitly.
You can use the class() function to check the data type of a variable.
Data types determine what operations can be performed on the data.
You can convert between different data types using built-in functions like as.integer(), as.numeric() and as.character()

Numeric Types

Description	Type	Example
integers or whole numbers	integer	`a <- as.integer(12)`
floating-point numbers	numeric	`b <- as.numeric(7.3)`
complex numbers	complex	`c <- as.complex(2i + 7)`

a <- 12L
b <- 7.3
c <- 2i + 7

cat("A:", a, class(a))
cat("B:", b, class(b))
cat("C:", c, class(c))

A: 12 integer

B: 7.3 numeric

C: 7+2i complex

Text Types

Description	Type	Example
textual data (strings)	character	`a <- "Jean Golding"`

name <- "Jean Golding"
cat("Name:", name, class(name))

Name: Jean Golding character

Note that

It’s important that when writing numbers in your scripts, you do not put quotation marks around them, otherwise they will be recognized by the R interpreter as strings. There is a difference between 3.14159 and “3.14159”, the first is a number and the second is just a string of characters.

pi <- 3.14159
cat("pi:", pi, class(pi))

pi: 3.14159 numeric

pi <- "3.14159"
cat("pi:", pi, class(pi))

pi: 3.14159 character

Boolean Types

Description	Type	Example
boolean values (True or False)	boolean	`a <- TRUE`

a <- 23
b <- 2
c <- a != b

cat("C:", c, class(c))

C: TRUE logical

Exercise

Without using R, can you tell what is the data type of these variables?

x <- 32
number_of_participants <- "1017"
Friday <- TRUE
y <- 1L
a <- 10<8

Answer

x is a numeric (float)

number_of_participants is a string

Friday is a boolean

y is an integer

a is a boolean