vec_fmt_bytes: Format a vector as values in terms of bytes

View source: R/format_vec.R

vec_fmt_bytesR Documentation

Format a vector as values in terms of bytes


With numeric values in a vector, we can transform each into byte values with human readable units. The vec_fmt_bytes() function allows for the formatting of byte sizes to either of two common representations: (1) with decimal units (powers of 1000, examples being "kB" and "MB"), and (2) with binary units (powers of 1024, examples being "KiB" and "MiB").

It is assumed the input numeric values represent the number of bytes and automatic truncation of values will occur. The numeric values will be scaled to be in the range of 1 to <1000 and then decorated with the correct unit symbol according to the standard chosen. For more control over the formatting of byte sizes, we can use the following options:

  • decimals: choice of the number of decimal places, option to drop trailing zeros, and a choice of the decimal symbol

  • digit grouping separators: options to enable/disable digit separators and provide a choice of separator symbol

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

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


  standard = c("decimal", "binary"),
  decimals = 1,
  n_sigfig = NULL,
  drop_trailing_zeros = TRUE,
  drop_trailing_dec_mark = TRUE,
  use_seps = TRUE,
  pattern = "{x}",
  sep_mark = ",",
  dec_mark = ".",
  force_sign = FALSE,
  incl_space = TRUE,
  locale = NULL,
  output = c("auto", "plain", "html", "latex", "rtf", "word")



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.


Standard used to express byte sizes

⁠singl-kw:[decimal|binary]⁠ // default: "decimal"

The form of expressing large byte sizes is divided between: (1) decimal units (powers of 1000; e.g., "kB" and "MB"), and (2) binary units (powers of 1024; e.g., "KiB" and "MiB").


Number of decimal places

scalar<numeric|integer>(val>=0) // default: 1

This corresponds to the exact number of decimal places to use. A value such as 2.34 can, for example, be formatted with 0 decimal places and it would result in "2". With 4 decimal places, the formatted value becomes "2.3400". The trailing zeros can be removed with drop_trailing_zeros = TRUE.


Number of significant figures

scalar<numeric|integer>(val>=1) // default: NULL (optional)

A option to format numbers to n significant figures. By default, this is NULL and thus number values will be formatted according to the number of decimal places set via decimals. If opting to format according to the rules of significant figures, n_sigfig must be a number greater than or equal to 1. Any values passed to the decimals and drop_trailing_zeros arguments will be ignored.


Drop any trailing zeros

⁠scalar<logical>⁠ // default: FALSE

A logical value that allows for removal of trailing zeros (those redundant zeros after the decimal mark).


Drop the trailing decimal mark

⁠scalar<logical>⁠ // default: TRUE

A logical value that determines whether decimal marks should always appear even if there are no decimal digits to display after formatting (e.g., 23 becomes 23. if FALSE). By default trailing decimal marks are not shown.


Use digit group separators

⁠scalar<logical>⁠ // default: TRUE

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.


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.


Separator mark for digit grouping

⁠scalar<character>⁠ // default: ","

The string to use as a separator between groups of digits. For example, using sep_mark = "," with a value of 1000 would result in a formatted value of "1,000". This argument is ignored if a locale is supplied (i.e., is not NULL).


Decimal mark

⁠scalar<character>⁠ // default: "."

The string to be used as the decimal mark. For example, using dec_mark = "," with the value 0.152 would result in a formatted value of "0,152"). This argument is ignored if a locale is supplied (i.e., is not NULL).


Forcing the display of a positive sign

⁠scalar<logical>⁠ // default: FALSE

Should the positive sign be shown for positive numbers (effectively showing a sign for all numbers except zero)? If so, use TRUE for this option. The default is FALSE, where only negative numbers will display a minus sign.


Include a space between the value and the units

⁠scalar<logical>⁠ // default: TRUE

An option for whether to include a space between the value and the units. The default is to use a space character for separation.


Locale identifier

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

An optional locale identifier that can be used for formatting values according the locale's rules. Examples include "en" for English (United States) and "fr" for French (France). We can use the info_locales() function as a useful reference for all of the locales that are supported. A locale ID can be also set in the initial gt() function call (where it would be used automatically by any function with a locale argument) but a locale value provided here will override that global locale.


Output format

⁠singl-kw:[auto|plain|html|latex|rtf|word]⁠ // default: "auto"

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(3.24294e14, 8, 1362902, -59027, NA)

Using vec_fmt_bytes() with the default options will create a character vector with values in bytes. 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).

#> [1] "324.3 TB" "8 B" "1.4 MB" "-59 kB" "NA"

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

vec_fmt_bytes(num_vals, decimals = 2)
#> [1] "324.29 TB" "8 B" "1.36 MB" "-59.03 kB" "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_bytes(num_vals, locale = "fi")
#> [1] "324,3 TB" "8 B" "1,4 MB" "-59 kB" "NA"

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

vec_fmt_bytes(num_vals, force_sign = TRUE)
#> [1] "+324.3 TB" "+8 B" "+1.4 MB" "-59 kB" "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_bytes(num_vals, pattern = "[{x}]")
#> [1] "[324.3 TB]" "[8 B]" "[1.4 MB]" "[-59 kB]" "NA"

Function ID


Function Introduced

v0.7.0 (Aug 25, 2022)

See Also

The variant function intended for formatting gt table data: fmt_bytes().

Other vector formatting functions: vec_fmt_currency(), vec_fmt_datetime(), vec_fmt_date(), vec_fmt_duration(), vec_fmt_engineering(), vec_fmt_fraction(), vec_fmt_index(), vec_fmt_integer(), vec_fmt_markdown(), vec_fmt_number(), vec_fmt_partsper(), vec_fmt_percent(), vec_fmt_roman(), vec_fmt_scientific(), vec_fmt_spelled_num(), vec_fmt_time()

gt documentation built on June 22, 2024, 11:11 a.m.