An Introduction to R Programming: Foundations of R Objects

At the most fundamental level, R does not operate on individual scalars, but on Atomic Vectors. Every object in R is a collection of elements of the same type, defined by their internal storage mode.

1. The Atomic Vector

Even a single value like z <- 100 is a vector of length one. R handles sequences of data—logical, integer, double, complex, character, and raw—as the primary unit of operation.

2. Assignment and Construction

We use the assignment operator <- to bind names to memory. Multi-element vectors are constructed using the c() (combine) function or the : (sequence) operator, such as z <- 0:9.

3. Internal Storage

The function typeof() reveals the low-level C-style representation of an object. For example, R distinguishes between numeric (floating point) and character (strings wrapped in ""). Atomic vectors ensure homogeneity: every element must be of the same type.

$$\text{typeof}(0:9) \rightarrow \text{"integer"}$$

TERMINAL bash — 80x24

> Ready. Click "Run" to execute.

QUESTION 1

In R, what is the length of the object created by z <- 100

0 (it is a scalar)

1 (it is an atomic vector of length 1)

Undefined until cast

100

QUESTION 2

Which function is used to reveal the low-level C-style storage type of an R object?

mode()

storage.class()

typeof()

class()

✅ Correct!

typeof() provides the most granular view of internal representation.

❌ Incorrect

While mode() and class() provide information, typeof() specifically reveals the low-level storage type.

QUESTION 3

Which of the following creates a sequence of integers from 0 to 9?

z <- seq(0, 9)

z <- 0:9

z <- c(0-9)

z <- atomic(0, 9)

✅ Correct!

The colon operator : is the standard shorthand for generating regular sequences.

❌ Incorrect

The : operator is used for sequences, while c() is for combining specific elements.

QUESTION 4

What is the requirement for elements within an 'atomic' vector?

They must be sorted.

They must be unique.

They must be of the same type (homogeneous).

They can be of mixed types.

QUESTION 5

What is the result of typeof("100")?

numeric

integer

character

logical

Case Study: Sensor Data Allocation

Homogeneity and Memory Allocation

A laboratory sensor records a single temperature reading. You need to store this in R, then later expand it to a sequence of 10 readings for a calibration test.

How would you initialize a single value '100' to a variable named 'z' and check its storage type?

Solution:
Use z <- 100typeof(z). R stores this as a numeric vector of length 1.

If you use z <- 0:9

Solution:
R allocates a contiguous block of memory for these atomic integer values, ensuring strict homogeneity of the sequence.

What happens if you attempt to combine the numeric 100 with the character 'Error' using c(100, 'Error')?

Solution:
Because atomic vectors must be homogeneous, R will coerce the numeric 100 into a character string "100" to match the other element.