Format values as a percentage

With numeric values in a gt table, we can perform percentage-based formatting. It is assumed the input numeric values are proportional values and, in this case, the values will be automatically multiplied by 100 before decorating with a percent sign (the other case is accommodated through setting scale_values = FALSE). For more control over percentage formatting, we can use the following options:

percent sign placement: the percent sign can be placed after or before the values and a space can be inserted between the symbol and the value.
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
value scaling toggle: choose to disable automatic value scaling in the situation that values are already scaled coming in (and just require the percent 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

Usage

fmt_percent(
  data,
  columns = everything(),
  rows = everything(),
  decimals = 2,
  drop_trailing_zeros = FALSE,
  drop_trailing_dec_mark = TRUE,
  scale_values = TRUE,
  use_seps = TRUE,
  accounting = FALSE,
  pattern = "{x}",
  sep_mark = ",",
  dec_mark = ".",
  force_sign = FALSE,
  placement = "right",
  incl_space = FALSE,
  system = c("intl", "ind"),
  locale = NULL
)

Arguments

data

The gt table data object

obj:<gt_tbl> // required

This is the gt table object that is commonly created through use of the gt() function.

columns

Columns to target

<column-targeting expression> // default: everything()

Can either be a series of column names provided in c(), a vector of column indices, or a select helper function (e.g. starts_with(), ends_with(), contains(), matches(), num_range() and everything()).

rows

Rows to target

<row-targeting expression> // default: everything()

In conjunction with columns, we can specify which of their rows should undergo formatting. The default everything() results in all rows in columns being formatted. Alternatively, we can supply a vector of row captions within c(), a vector of row indices, or a select helper function (e.g. starts_with(), ends_with(), contains(), matches(), num_range(), and everything()). We can also use expressions to filter down to the rows we need (e.g., [colname_1] > 100 & [colname_2] < 50).

decimals

Number of decimal places

scalar<numeric|integer>(val>=0) // default: 2

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".

drop_trailing_zeros

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_trailing_dec_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.

scale_values

Multiply input values by 100

scalar<logical> // default: TRUE

Should the values be scaled through multiplication by 100? By default this scaling is performed since the expectation is that incoming values are usually proportional. Setting to FALSE signifies that the values are already scaled and require only the percent sign when formatted.

use_seps

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.

accounting

Use accounting style

scalar<logical> // default: FALSE

An option to use accounting style for values. Normally, negative values will be shown with a minus sign but using accounting style will instead put any negative values in parentheses.

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.

sep_mark

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).

dec_mark

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).

force_sign

Forcing the display of a positive sign

scalar<logical> // default: FALSE

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. This option is disregarded when using accounting notation with accounting = TRUE.

placement

Percent sign placement

singl-kw:[right|left] // default: "right"

This option governs the placement of the percent sign. This can be either be "right" (the default) or "left".

incl_space

Include a space between the value and the % sign

scalar<logical> // default: FALSE

An option for whether to include a space between the value and the percent sign. The default is to not introduce a space character.

system

Numbering system for grouping separators

singl-kw:[intl|ind] // default: "intl"

The international numbering system (keyword: "intl") is widely used and its grouping separators (i.e., sep_mark) are always separated by three digits. The alternative system, the Indian numbering system (keyword: "ind"), uses grouping separators that correspond to thousand, lakh, crore, and higher quantities.

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. 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.

Value

An object of class gt_tbl.

Compatibility of formatting function with data values

fmt_percent() is compatible with body cells that are of the "numeric" or "integer" types. Any other types of body cells are ignored during formatting. This is to say that cells of incompatible data types may be targeted, but there will be no attempt to format them.

Compatibility of arguments with the `from_column()` helper function

from_column() can be used with certain arguments of fmt_percent() to obtain varying parameter values from a specified column within the table. This means that each row could be formatted a little bit differently. These arguments provide support for from_column():

decimals
drop_trailing_zeros
drop_trailing_dec_mark
scale_values
use_seps
accounting
pattern
sep_mark
dec_mark
force_sign
incl_space
placement
system
locale

Please note that for all of the aforementioned arguments, a from_column() call needs to reference a column that has data of the correct type (this is different for each argument). Additional columns for parameter values can be generated with cols_add() (if not already present). Columns that contain parameter data can also be hidden from final display with cols_hide(). Finally, there is no limitation to how many arguments the from_column() helper is applied so long as the arguments belong to this closed set.

Adapting output to a specific `locale`

This formatting function can adapt outputs according to a provided locale value. Examples include "en" for English (United States) and "fr" for French (France). The use of a valid locale ID here means separator and decimal marks will be correct for the given locale. Should any values be provided in sep_mark or dec_mark, they will be overridden by the locale's preferred values.

Note that a locale value provided here will override any global locale setting performed in gt()'s own locale argument (it is settable there as a value received by all other functions that have a locale argument). As a useful reference on which locales are supported, we can callinfo_locales() to view an info table.

Examples

Use a summarized version of the pizzaplace dataset to create a gt table. With fmt_percent(), we can format the frac_of_quota column to display values as percentages (to one decimal place).

pizzaplace |>
  dplyr::mutate(month = as.numeric(substr(date, 6, 7))) |>
  dplyr::count(month, name = "pizzas_sold") |>
  dplyr::mutate(frac_of_quota = pizzas_sold / 4000) |>
  gt(rowname_col = "month") |>
  fmt_percent(
    columns = frac_of_quota,
    decimals = 1
  )

This image of a table was generated from the first code example in the `fmt_percent()` help file.

Function ID

3-5

Function Introduced

v0.2.0.5 (March 31, 2020)

Usage

Arguments

Value

Compatibility of formatting function with data values

Compatibility of arguments with the from_column() helper function

Adapting output to a specific locale

Examples

Function ID

Function Introduced

See also

Compatibility of arguments with the `from_column()` helper function

Adapting output to a specific `locale`