Format a vector as Roman numerals

With numeric values in a vector, we can transform those to Roman numerals, rounding values as necessary.

Usage

vec_fmt_roman(
  x,
  case = c("upper", "lower"),
  pattern = "{x}",
  output = c("auto", "plain", "html", "latex", "rtf", "word")
)

Arguments

x

The input vector

vector(numeric|integer) // required

This is the input vector that will undergo transformation to a character vector of the same length. Values within the vector will be formatted.

case

Use uppercase or lowercase letters

singl-kw:[upper|lower] // default: "upper"

Should Roman numerals should be rendered as uppercase ("upper") or lowercase ("lower") letters? By default, this is set to "upper".

pattern

Specification of the formatting pattern

scalar<character> // default: "{x}"

A formatting pattern that allows for decoration of the formatted value. The formatted value is represented by the {x} (which can be used multiple times, if needed) and all other characters will be interpreted as string literals.

output

Output format

The output style of the resulting character vector. This can either be "auto" (the default), "plain", "html", "latex", "rtf", or "word". In knitr rendering (i.e., Quarto or R Markdown), the "auto" option will choose the correct output value

Value

A character vector.

Examples

Let's create a numeric vector for the next few examples:

num_vals <- c(1, 4, 5, 8, 12, 20, 0, -5, 1.3, NA)

Using vec_fmt_roman() with the default options will create a character vector with values rendered as Roman numerals. Zero values will be rendered as "N", any NA values remain as NA values, negative values will be automatically made positive, and values greater than or equal to 3900 will be rendered as "ex terminis". The rendering context will be autodetected unless specified in the output argument (here, it is of the "plain" output type).

vec_fmt_roman(num_vals)

#> [1] "I" "IV" "V" "VIII" "XII" "XX" "N" "V" "I" "NA"

We can also use vec_fmt_roman() with the case = "lower" option to create a character vector with values rendered as lowercase Roman numerals.

vec_fmt_roman(num_vals, case = "lower")

#> [1] "i" "iv" "v" "viii" "xii" "xx" "n" "v" "i" "NA"

As a last example, one can wrap the values in a pattern with the pattern argument. Note here that NA values won't have the pattern applied.

vec_fmt_roman(num_vals, case = "lower", pattern = "{x}.")

#> [1] "i." "iv." "v." "viii." "xii." "xx." "n." "v." "i." "NA"

Function ID

15-10

Function Introduced

v0.8.0 (November 16, 2022)