roman {utils}

R Documentation

Roman Numerals

Description

Manipulate integers as roman numerals.

Usage

as.roman(x)

Arguments

x	a numeric vector, or a character vector of arabic or roman numerals.

Details

as.roman creates objects of class "roman" which are internally represented as integers, and have suitable methods for printing, formatting, subsetting, and coercion to character.

Only numbers between 1 and 3899 have a unique representation as roman numbers.

References

Wikipedia contributors (2006). Roman numerals. Wikipedia, The Free Encyclopedia. http://en.wikipedia.org/w/index.php?title=Roman_numerals&oldid=78252134. Accessed September 29, 2006.

Examples

## First five roman 'numbers'.
(y <- as.roman(1 : 5))
## Middle one.
y[3]
## Current year as a roman number.
(y <- as.roman(format(Sys.Date(), "%Y")))
## 10 years ago ...
y - 10

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