R Series

Built-in Constants R

In this article, you’ll learn about constants in R. And how to use them.

Constants, as the name suggests, are entities whose value cannot be altered. Basic types of constant are numeric constants and character constants.

Numeric Constants

All numbers fall under this category. They can be of type integer, double or complex.

It can be checked with the typeof() function.

Numeric constants followed by L are regarded as integer and those followed by i are regarded as complex.

> typeof(101)
[1] "double"
> typeof(101L)
[1] "integer"
> typeof(101i)
[1] "complex"

Also, numeric constants preceded by 0x or 0X are interpreted as hexadecimal numbers.

> 0xf
[1] 15
> 0xaf
[1] 175

Character Constants

Character constants can be represented using either single quotes (‘) or double quotes (“) as delimiters.

> 'Hello World'
[1] "Hello World"
> typeof("Hello World")
[1] "character"

Built in Constants

Some of the built-in constants defined in R

Usage

> LETTERS
 [1] "A" "B" "C" "D" "E" "F" "G" "H" "I" "J" "K" "L" "M" "N" "O" "P" "Q" "R" "S"
[20] "T" "U" "V" "W" "X" "Y" "Z"
> letters
 [1] "a" "b" "c" "d" "e" "f" "g" "h" "i" "j" "k" "l" "m" "n" "o" "p" "q" "r" "s"
[20] "t" "u" "v" "w" "x" "y" "z"
> month.abb
 [1] "Jan" "Feb" "Mar" "Apr" "May" "Jun" "Jul" "Aug" "Sep" "Oct" "Nov" "Dec"
> month.name
 [1] "January"   "February"  "March"     "April"     "May"       "June"
 [7] "July"      "August"    "September" "October"   "November"  "December"
> pi
[1] 3.141593

Details

Constant	Description
`LETTERS`	the 26 upper-case letters of the Roman alphabet.
`letters`	the 26 lower-case letters of the Roman alphabet.
`month.abb`	the three-letter abbreviations for the English month names.
`month.name`	the English names for the months of the year.
`pi`	the ratio of the circumference of a circle to its diameter.

Note: Since R is a case sensitive language therefore TRUE and True are not the same. Here, TRUE is a reserved word and True can be a variable name.