Gist for the R Data Types tutorial

data_types_gist.R

# assign value 3 to variable radius
radius <- 3

# assign value 3.14 to variable pi
pi <- 3.14

# compute the area of the circle and assign it to 
# a variable of the same name
area <- pi * radius * radius

# access radius
radius

# access area
area

# numeric data type
# create two variables
number1 <- 3.5
number2 <- 3

# test the type of the variables
class(number1)
class(number2)

# check if variable is of type numeric
is.numeric(number1)
is.numeric(number2)

# integer data types
# create variable and assign an integer
number1 <- 3
class(number1)

# specify the variable to be integer
number2 <- as.integer(3)
class(number2)

# test if a variable is an integer
is.integer(number1)
is.integer(number2)

# coerce other data types to type integer
number3 <- 3
class(number3)

# coerce to type integer
number3 <- as.integer(number3)
class(number3)

# character data
name <- 'John'
class(name)

# returns NA
as.integer(name)

# logical data
x <- c(TRUE, FALSE)
as.integer(x)

# character data type
first_name <- "Jovial"
last_name <- 'Mann'

first_name
last_name

# error if quotes not used
name <- Tom

# test data type
is.character(first_name)
class(last_name)


# logical data types
x <- TRUE
y <- FALSE

# test data types
class(x)
is.logical(y)

# use comparison operators
x > y
x < y
x == y

# store output in a new variable
z <- x != y
class(z)

# TRUE and FALSE are represented by 1 and 0
as.logical(1)
as.logical(0)
as.numeric(TRUE)
as.numeric(FALSE)
as.logical(c(-2, -1, 0, 1, 1.5))


# coerce other data types to type logical
# create variables of different data types
age <- as.integer(25)   # integer
score <- 3.8            # numeric
name <- 'John'          # character
today <- Sys.time()     # date/time

# coerce the above to type logical
as.logical(age)
as.logical(score)
as.logical(name)
as.logical(today)


# date and time
# returns date
Sys.Date()    

# returns day, month, date, time and year
date()          

# returns date and time
Sys.time()      

# returns timezone
Sys.timezone()  

# different ways to represent date and time
# dd-mm-yyyy
date <- as.Date("27/09/2015", format = "%d/%m/%Y")
date
# mm-dd-yyyy
date <- as.Date("09/27/2015", format = "%m/%d/%Y")
date
# dd-mm-yyyy
date <- as.Date("September 27,2015", format = "%B %d, %Y")
date