Format a vector as indexed characters

With numeric values in a vector, we can transform those to index values, usually based on letters. These characters can be derived from a specified locale and they are intended for ordering (often leaving out characters with diacritical marks).

Usage

vec_fmt_index(
  x,
  case = c("upper", "lower"),
  index_algo = c("repeat", "excel"),
  pattern = "{x}",
  locale = NULL,
  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 the resulting index characters be rendered as uppercase ("upper") or lowercase ("lower") letters? By default, this is set to "upper".

index_algo

Indexing algorithm

singl-kw:[repeat|excel] // default: "repeat"

The indexing algorithm handles the recycling of the index character set. By default, the "repeat" option is used where characters are doubled, tripled, and so on, when moving past the character set limit. The alternative is the "excel" option, where Excel-based column naming is adapted and used here (e.g., [..., Y, Z, AA, AB, ...]).

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.

locale

Locale identifier

scalar<character> // default: NULL (optional)

An optional locale identifier that can be used for formatting values according to the locale's rules. Examples include "en" for English (United States) and "fr" for French (France). We can call info_locales() for a useful reference for all of the locales that are supported.

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, 26, 34, 0, -5, 1.3, NA)

Using vec_fmt_index() with the default options will create a character vector with values rendered as index numerals. Zero values will be rendered as "" (i.e., empty strings), any NA values remain as NA values, and negative values will be automatically made positive. The rendering context will be autodetected unless specified in the output argument (here, it is of the "plain" output type).

vec_fmt_index(num_vals)

#> [1] "A" "D" "E" "H" "L" "T" "Z" "HH" "" "E" "A" "NA"

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

vec_fmt_index(num_vals, case = "lower")

#> [1] "a" "d" "e" "h" "l" "t" "z" "hh" "" "e" "a" "NA"

If we are formatting for a different locale, we could supply the locale ID and let gt obtain a locale-specific set of index values:

vec_fmt_index(1:10, locale = "so")

#> [1] "B" "C" "D" "F" "G" "H" "J" "K" "L" "M"

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

#> [1] "a." "d." "e." "h." "l." "t." "z." "hh." "." "e." "a." "NA"

Function ID

15-10

Function Introduced

v0.9.0 (Mar 31, 2023)