Atomic Modes

Vectors in R are essentially dimensionless sequences of homogeneously typed elements. These elements can have one of six types, called atomic modes.

  1. Numeric/Double
  2. Integer
  3. Complex
  4. Logical
  5. Character
  6. Raw

The first three types represent different types of numeric data, while the last three types represent different types of non-numeric data. It’s important to note that all the elements in a given vector must have the same type.

Numeric/Double

Note

R’s numeric mode is equivalent to a double-precision floating point value.

Numeric vectors store real numbers (e.g., 6.01, 0.04, -42.1, 1.0). The numeric mode is the default type for numbers in R, so if we store a number in an object without specifying otherwise, the type of that object will be numeric (even if the value is a whole number).

v1 <- vector("numeric", 3)
v1
[1] 0 0 0
v1 <- vector("double", 3)
v1
[1] 0 0 0

Integer

Note

R’s integer mode is equivalent to a signed long integer.

The integer type represents whole numbers (e.g., 1, 100, -5, 0). While integers and numeric (double) values may look similar, they are distinct types in R. Integers are used when exact whole-number representation is needed. They can also offer slight computational advantages in terms of memory usage and performance, especially when working with large datasets.

v2 <- vector("integer", 3)
v2
[1] 0 0 0

Complex

The complex type represents complex numbers (e.g., \(3.0 + 4.1i\), \(-0.2 + 8.01i\), \(3.1 - 27.0i\)). In R, complex numbers are written with an i to indicate the imaginary unit, like 1+2i or 0-3.5i.

v3 <- vector("complex",3)
v3
[1] 0+0i 0+0i 0+0i

Logical

Logical vectors store boolean values (i.e., true, false). Logical vectors can only contain the values TRUE or FALSE.

v4 <- vector("logical", 3)
v4
[1] FALSE FALSE FALSE

Character

Note

R doesn’t have separate string and character types: any string-like data is represented via character vectors.

The character type is used to represent text. Character vectors contain strings, which are sequences of characters enclosed in quotation marks (e.g., “foo”, “bar”, “alice & bob”, “42”, “FALSE”).

v4 <- vector("character", 3)
v4
[1] "" "" ""

Raw

The raw type represents raw bytes of data, typically used for low-level operations. This type is rarely used in typical data analyses.

v6 <- vector("raw", 3)
v6
[1] 00 00 00
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