In answer to a question on R-help John Fox provided an elegant R function to translate integers into English numbers. The present package extends this code to an S3 class, with constructor functions and methods to make this original idea more conveniently available.
The function as.english is intended to provide a
parallel facility to the function as.roman in the
utils package.
The main purpose of the package is to present an interesting programming example rather than to solve a likely real problem, though there could well be some applications in unusual contexts.
Note added in Version 1.1-4. The two small helper functions
words and Words are included to facilitate
inline code inserts in R markdown files. See the help files for
examples. The ordinal function produces character strings
and may be used directly in inline code inserts. Use
`r words(103)` rather than `r english(103)` in
R markdown files.
Note added in Version 1.2-0. The function indefinite
added for algorithmically including an apprporiate indefinite article in
a document insert. Based on a suggestion of Anne Pier Salverda.
The capitalised version, Indefinite, was added in
1.2-1.
This vignette was added in 1.2-2.
The main use envisaged for these tools is for code inserts in either R markdown or R noweb documents. It is easier here to demonstrate their function in plain code chunks, as below.
The resolution of an integer into words depends on the style of
English chosen. English (UK) style inserts the conjunction and
in various places where American (USA) style omits it. Wheter or not
this happens is governed by the english.UK option, (a
logical variable, TRUE for UK English), but if this option
is unset, a guess is made as to which style is needed depending on the
user’s locale.
soldiers <- 10006
oldOpt <- options(english.UK = TRUE)
cat("The Duke of York had approximately", words(soldiers), "men.\n")
cat("How many did you say? ", Words(soldiers), ", approximately.\n", sep = "")
The Duke of York had approximately ten thousand and six men.
How many did you say? Ten thousand and six, approximately.options(english.UK = FALSE)
cat("The Duke of York had approximately", words(soldiers), "men.\n")
cat("How many did you say? ", Words(soldiers), ", approximately.\n", sep = "")
options(oldOpt)
The Duke of York had approximately ten thousand six men.
How many did you say? Ten thousand six, approximately.Ordinal numbers are handled as well.
days <- 1:6
cat(paste("\nOn the", ordinal(days), "day of Christmas..."))
On the first day of Christmas...
On the second day of Christmas...
On the third day of Christmas...
On the fourth day of Christmas...
On the fifth day of Christmas...
On the sixth day of Christmas...The indefinite article, “a” or “an”, can be algorithmically chosen and prepended, either in lower case or capitalised:
steps <- 7:11
cat(paste0("\nThis is ", indefinite(steps), "-step process..."))
This is a seven-step process...
This is an eight-step process...
This is a nine-step process...
This is a ten-step process...
This is an eleven-step process...
cat(paste0("\nThis is ", indefinite(steps, words = FALSE), "-step process..."))
This is a 7-step process...
This is an 8-step process...
This is a 9-step process...
This is a 10-step process...
This is an 11-step process...
cat(paste0("\n", Indefinite(ordinal(steps)), " step of the process is..."))
A seventh step of the process is...
An eighth step of the process is...
A ninth step of the process is...
A tenth step of the process is...
An eleventh step of the process is...Roman notation is provided by the utils::as.roman
function in a similar way:
numbers <- c(1:10, 1999, 2019)
punct <- c(rep(",", 10), " and",".")
cat(c("In Roman notation:",
paste0("\n\t", Words(numbers), " is written as \"",
utils::as.roman(numbers),"\"", punct)))
cat("\nDoing arithmetic in Roman notation can be difficult.")
In Roman notation:
One is written as "I",
Two is written as "II",
Three is written as "III",
Four is written as "IV",
Five is written as "V",
Six is written as "VI",
Seven is written as "VII",
Eight is written as "VIII",
Nine is written as "IX",
Ten is written as "X",
One thousand nine hundred ninety-nine is written as "MCMXCIX" and
Two thousand nineteen is written as "MMXIX".
Doing arithmetic in Roman notation can be difficult.Some arithmetic operations are allowed for english
objects, but to make sense the result should be in whole numbers.