A Appendix A

A.1 Basic Data Structure in R

Though in the book, most of the time we talk about data frames (sometimes tibble), vectors are the buliding blocks of them. Traditional learners of R usually start learning it using vectors. However, for accountants (or would-be accountants) it is better to begin with tibbles and work down to the underlying concepts such as vectors.

Basically there are two types of vectors in R; one is called Atomic vectors (also called homogeneous vectors) and the other is called lists. Atomic vectors contain similar types of elements, while lists vectors do not; lists can hold differnet types elements in a vector. There are six types of Atomic vectors - logical, integer, double, character, complex, and raw. The integerand double are together called numeric. Of these types, the first four are widely used and most relevant for accounting analytics.

Each vector has 2 major characteristis - type and length. The function typeof can be used to know about the types of the vectors - namely logical, integer, double, character, complex, or raw. The length function is used to get or set the length of a vector. The function nchar can be used to get the length of a string. Some examples of vectors are given below -

# Character type 
a <- c("1933","1934","2002")
length(a)

## [1] 3

typeof(a)

## [1] "character"

a

## [1] "1933" "1934" "2002"

b <- c("The Securities Act", "The Securities Exchange Act", "Sarbanes-Oxley Act")
length(b)

## [1] 3

typeof(b)

## [1] "character"

nchar(b)

## [1] 18 27 18

b

## [1] "The Securities Act"         
## [2] "The Securities Exchange Act"
## [3] "Sarbanes-Oxley Act"

# Logical type 
c <- c(TRUE, FALSE, TRUE, TRUE, TRUE, FALSE)
length(c)

## [1] 6

typeof(c)

## [1] "logical"

c

## [1]  TRUE FALSE  TRUE  TRUE  TRUE FALSE

# Double type 
d <- c(1933, 1934, 2002)
length(d)

## [1] 3

typeof(d)

## [1] "double"

d

## [1] 1933 1934 2002

# Integer type 
e <- c(1933L, 1934L, 2002L)
length(e)

## [1] 3

typeof(e)

## [1] "integer"

e

## [1] 1933 1934 2002

f <- list(a,b,c,d,e)
length(f)

## [1] 5

typeof(f)

## [1] "list"

f

## [[1]]
## [1] "1933" "1934" "2002"
## 
## [[2]]
## [1] "The Securities Act"         
## [2] "The Securities Exchange Act"
## [3] "Sarbanes-Oxley Act"         
## 
## [[3]]
## [1]  TRUE FALSE  TRUE  TRUE  TRUE FALSE
## 
## [[4]]
## [1] 1933 1934 2002
## 
## [[5]]
## [1] 1933 1934 2002

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