• Basic data types in R, str()
• Categorical data
• class() and converting variables
• Vector and matrix fun

Data objects are storage containers

x <- 1 # single numeric integer

y <- c(4.43, 2.70) # vector of numeric decimal values

z <- c("Bob", "Karen") # vector of character strings

• Can contain letters, numbers, some symbolic characters

• Must begin with a letter

• Must not contain spaces

• No forbidden characters like ‘+’, ‘-’, ‘@’, and others

• Should be human-readable, consistent, and not too long

• Case sensitive

A factor is data where the different values are categories

• Ordered factor

'Monday', 'Tuesday', 'Wednesday...'

• Non-ordered factor

"Staffordshire", "Lancashire"...

Generally need to think about this when analysing data

• The class() function can be use to see what R thinks your variable class is

• Also, the Global Environment

Vector

• stores data in a single dimension from 1 to i, my_vec[i]

Matrix

• stores data in two dimensions 1 to i rows, 1 to j columns my_mat[i, j]

Array

• 3 dimensions to i, j, and k my_array[i, j, k]