# roman

0th

Percentile

##### Roman Numerals

Simple manipulation of (a small set of) integer numbers as roman numerals.

Keywords
arith
##### Usage
as.roman(x)
.romans
##### Arguments
x

a numeric or 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, coercion, etc, see methods(class = "roman").

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

.romans is the basic dictionary, a named character vector.

##### References

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

• as.roman
• .romans
##### Examples
library(utils) # NOT RUN { ## First five roman 'numbers'. (y <- as.roman(1 : 5)) ## Middle one. y ## Current year as a roman number. (y <- as.roman(format(Sys.Date(), "%Y"))) ## Today, and 10, 20, 30, and 100 years ago ... y - 10*c(0:3,10) # } # NOT RUN { ## mixture of arabic and roman numbers : as.roman(c(NA, 1:3, "", strrep("I", 1:6))) # + NA with a warning for "IIIIII" cc <- c(NA, 1:3, strrep("I", 0:5)) (rc <- as.roman(cc)) # two NAs: 0 is not "roman" (ic <- as.integer(rc)) # works automitcally [without an explicit method] ## simple consistency checks -- arithmetic when result is in {1,2,..,3899} : stopifnot(identical(rc, as.roman(rc)), # as.roman(.) is "idempotent" identical(rc + rc + (3*rc), rc*5), identical(ic, c(NA, 1:3, NA, 1:5)), identical(as.integer(5*rc), 5L*ic), identical(as.numeric(rc), as.numeric(ic)), identical(as.list(rc), as.list(ic))) # } 
Documentation reproduced from package utils, version 3.5.1, License: Part of R 3.5.1

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