Format a vector as values in scientific notation

With numeric values in a vector, we can perform formatting so that the input values are rendered into scientific notation within the output character vector. The following major options are available:

decimals: choice of the number of decimal places, option to drop trailing zeros, and a choice of the decimal symbol
scaling: we can choose to scale targeted values by a multiplier value
pattern: option to use a text pattern for decoration of the formatted values
locale-based formatting: providing a locale ID will result in formatting specific to the chosen locale

Usage

vec_fmt_scientific(
  x,
  decimals = 2,
  drop_trailing_zeros = FALSE,
  scale_by = 1,
  pattern = "{x}",
  sep_mark = ",",
  dec_mark = ".",
  force_sign = FALSE,
  locale = NULL,
  output = c("auto", "plain", "html", "latex", "rtf", "word")
)

Arguments

x: A numeric vector.
decimals: An option to specify the exact number of decimal places to use. The default number of decimal places is 2.
drop_trailing_zeros: A logical value that allows for removal of trailing zeros (those redundant zeros after the decimal mark).
scale_by: A value to scale the input. The default is 1.0. All numeric values will be multiplied by this value first before undergoing formatting.
pattern: 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.
sep_mark: 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).
dec_mark: The character to use as a decimal mark (e.g., using dec_mark = "," with 0.152 would result in a formatted value of 0,152).
force_sign: Should the positive sign be shown for positive values (effectively showing a sign for all values except zero)? If so, use TRUE for this option. The default is FALSE, where only negative numbers will display a minus sign.
locale: 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.
output: 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(3.24e-4, 8.65, 1362902.2, -59027.3, NA)

Using vec_fmt_scientific() with the default options will create a character vector with values in scientific notation. Any NA values remain as NA values. The rendering context will be autodetected unless specified in the output argument (here, it is of the "plain" output type).

vec_fmt_scientific(num_vals)

#> [1] "3.24 × 10^-4" "8.65" "1.36 × 10^6" "-5.90 × 10^4" "NA"

We can change the number of decimal places with the decimals option:

vec_fmt_scientific(num_vals, decimals = 1)

#> [1] "3.2 × 10^-4" "8.7" "1.4 × 10^6" "-5.9 × 10^4" "NA"

If we are formatting for a different locale, we could supply the locale ID and gt will handle any locale-specific formatting options:

vec_fmt_scientific(num_vals, locale = "es")

#> [1] "3,24 × 10^-4" "8,65" "1,36 × 10^6" "-5,90 × 10^4" "NA"

Should you need to have positive and negative signs on each of the output values, use force_sign = TRUE:

vec_fmt_scientific(num_vals, force_sign = TRUE)

#> [1] "+3.24 × 10^-4" "+8.65" "+1.36 × 10^6" "-5.90 × 10^4" "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_scientific(num_vals, pattern = "[{x}]")

#> [1] "[3.24 × 10^-4]" "[8.65]" "[1.36 × 10^6]" "[-5.90 × 10^4]" "NA"

Function ID

14-3