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With numeric values in vector, we can perform mixed-fraction-based formatting. There are several options for setting the accuracy of the fractions. Furthermore, there is an option for choosing a layout (i.e., typesetting style) for the mixed-fraction output.

The following options are available for controlling this type of formatting:

  • accuracy: how to express the fractional part of the mixed fractions; there are three keyword options for this and an allowance for arbitrary denominator settings

  • simplification: an option to simplify fractions whenever possible

  • layout: We can choose to output values with diagonal or inline fractions

  • digit grouping separators: options to enable/disable digit separators and provide a choice of separator symbol for the whole number portion

  • pattern: option to use a text pattern for decoration of the formatted mixed fractions

  • locale-based formatting: providing a locale ID will result in number formatting specific to the chosen locale


  accuracy = NULL,
  simplify = TRUE,
  layout = c("inline", "diagonal"),
  use_seps = TRUE,
  pattern = "{x}",
  sep_mark = ",",
  locale = NULL,
  output = c("auto", "plain", "html", "latex", "rtf", "word")



A numeric vector.


The type of fractions to generate. This can either be one of the keywords "low", "med", or "high" (to generate fractions with denominators of up to 1, 2, or 3 digits, respectively) or an integer value greater than zero to obtain fractions with a fixed denominator (2 yields halves, 3 is for thirds, 4 is quarters, etc.). For the latter option, using simplify = TRUE will simplify fractions where possible (e.g., 2/4 will be simplified as 1/2). By default, the "low" option is used.


If choosing to provide a numeric value for accuracy, the option to simplify the fraction (where possible) can be taken with TRUE (the default). With FALSE, denominators in fractions will be fixed to the value provided in accuracy.


For HTML output, the "inline" layout is the default. This layout places the numerals of the fraction on the baseline and uses a standard slash character. The "diagonal" layout will generate fractions that are typeset with raised/lowered numerals and a virgule.


An option to use digit group separators. The type of digit group separator is set by sep_mark and overridden if a locale ID is provided to locale. This setting is TRUE by default.


A formatting pattern that allows for decoration of the formatted value. The value itself is represented by {x} and all other characters are taken to be string literals.


The mark to use as a separator between groups of digits (e.g., using sep_mark = "," with 1000 would result in a formatted value of 1,000).


An optional locale ID that can be used for formatting the value according the locale's rules. Examples include "en" for English (United States) and "fr" for French (France). The use of a valid locale ID will override any values provided in sep_mark and dec_mark. We can use the info_locales() function as a useful reference for all of the locales that are supported.


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


A character vector.


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

num_vals <- c(0.0052, 0.08, 0, -0.535, NA)

Using vec_fmt_fraction() will create a character vector of fractions. Any NA values will render as "NA". The rendering context will be autodetected unless specified in the output argument (here, it is of the "plain" output type).

#> [1] "0" "1/9" "0" "-5/9" "NA"

There are many options for formatting as fractions. If you'd like a higher degree of accuracy in the computation of fractions we can supply the "med" or "high" keywords to the accuracy argument:

vec_fmt_fraction(num_vals, accuracy = "high")

#> [1] "1/200" "2/25" "0" "-107/200" "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_fraction(num_vals, accuracy = 8, pattern = "[{x}]")

#> [1] "[0]" "[1/8]" "[0]" "[-1/2]" "NA"

Function ID