fmt_percent: Format values as a percentage

Description

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 though setting the scale_values to 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
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,
  rows = NULL,
  decimals = 2,
  drop_trailing_zeros = FALSE,
  drop_trailing_dec_mark = TRUE,
  scale_values = TRUE,
  use_seps = TRUE,
  pattern = "{x}",
  sep_mark = ",",
  dec_mark = ".",
  incl_space = FALSE,
  placement = "right",
  locale = NULL
)

Arguments

data

A table object that is created using the gt() function.

columns

The columns to format. Can either be a series of column names provided in vars(), a vector of column indices, or a helper function focused on selections. The select helper functions are: starts_with(), ends_with(), contains(), matches(), one_of(), and everything().

rows

Optional rows to format. Not providing any value results in all rows in columns being formatted. Can either be a vector of row captions provided c(), a vector of row indices, or a helper function focused on selections. The select helper functions are: starts_with(), ends_with(), contains(), matches(), one_of(), and everything(). We can also use expressions to filter down to the rows we need (e.g., [colname_1] > 100 & [colname_2] < 50).

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).

drop_trailing_dec_mark

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.). The default for this is TRUE, which means that trailing decimal marks are not shown.

scale_values

Should the values be scaled through multiplication by 100? By default this is TRUE since the expectation is that normally values are proportions. Setting to FALSE signifies that the values are already scaled and require only the percent sign when formatted.

use_seps

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.

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).

incl_space

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

placement

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

locale

An optional locale ID that can be used for formatting the value according the locale's rules. Examples include "en_US" for English (United States) and "fr_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.

Value

An object of class gt_tbl.

Figures

Function ID

3-3

Details

Targeting of values is done through columns and additionally by rows (if nothing is provided for rows then entire columns are selected). A number of helper functions exist to make targeting more effective. Conditional formatting is possible by providing a conditional expression to the rows argument. See the Arguments section for more information on this.

Examples

Run this code

# NOT RUN {
# Use `pizzaplace` to create a gt table;
# format the `frac_of_quota` column to
# display values as percentages
tab_1 <-
  pizzaplace %>%
  dplyr::mutate(month = as.numeric(substr(date, 6, 7))) %>%
  dplyr::group_by(month) %>%
  dplyr::summarize(pizzas_sold = dplyr::n()) %>%
  dplyr::ungroup() %>%
  dplyr::mutate(frac_of_quota = pizzas_sold / 4000) %>%
  gt(rowname_col = "month") %>%
  fmt_percent(
    columns = vars(frac_of_quota),
    decimals = 1
  )

# }

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