Format numeric or duration values as styled time duration strings

Format input values to time duration values whether those input values are numbers or of the difftime class. We can specify which time units any numeric input values have (as weeks, days, hours, minutes, or seconds) and the output can be customized with a duration style (corresponding to narrow, wide, colon-separated, and ISO forms) and a choice of output units ranging from weeks to seconds.

Usage

fmt_duration(
  data,
  columns = everything(),
  rows = everything(),
  input_units = NULL,
  output_units = NULL,
  duration_style = c("narrow", "wide", "colon-sep", "iso"),
  trim_zero_units = TRUE,
  max_output_units = NULL,
  pattern = "{x}",
  use_seps = TRUE,
  sep_mark = ",",
  force_sign = 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. Examples of select helper functions include starts_with(), ends_with(), contains(), matches(), one_of(), 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. Examples of select helper functions include starts_with(), ends_with(), contains(), matches(), one_of(), 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).

input_units

Declaration of duration units for numerical values

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

If one or more selected columns contains numeric values (not difftime values, which contain the duration units), a keyword must be provided for input_units for gt to determine how those values are to be interpreted in terms of duration. The accepted units are: "seconds", "minutes", "hours", "days", and "weeks".

output_units

Choice of output units

mult-kw:[weeks|days|hours|minutes|seconds] // default: NULL (optional)

Controls the output time units. The default, NULL, means that gt will automatically choose time units based on the input duration value. To control which time units are to be considered for output (before trimming with trim_zero_units) we can specify a vector of one or more of the following keywords: "weeks", "days", "hours", "minutes", or "seconds".

duration_style

Style for representing duration values

singl-kw:[narrow|wide|colon-sep|iso] // default: "narrow"

A choice of four formatting styles for the output duration values. With "narrow" (the default style), duration values will be formatted with single letter time-part units (e.g., 1.35 days will be styled as "1d 8h 24m"). With "wide", this example value will be expanded to "1 day 8 hours 24 minutes" after formatting. The "colon-sep" style will put days, hours, minutes, and seconds in the "([D]/)[HH]:[MM]:[SS]" format. The "iso" style will produce a value that conforms to the ISO 8601 rules for duration values (e.g., 1.35 days will become "P1DT8H24M").

trim_zero_units

Trimming of zero values

scalar<logical>|mult-kw:[leading|trailing|internal] // default: TRUE

Provides methods to remove output time units that have zero values. By default this is TRUE and duration values that might otherwise be formatted as "0w 1d 0h 4m 19s" with trim_zero_units = FALSE are instead displayed as "1d 4m 19s". Aside from using TRUE/FALSE we could provide a vector of keywords for more precise control. These keywords are: (1) "leading", to omit all leading zero-value time units (e.g., "0w 1d" -> "1d"), (2) "trailing", to omit all trailing zero-value time units (e.g., "3d 5h 0s" -> "3d 5h"), and "internal", which removes all internal zero-value time units (e.g., "5d 0h 33m" -> "5d 33m").

max_output_units

Maximum number of time units to display

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

If output_units is NULL, where the output time units are unspecified and left to gt to handle, a numeric value provided for max_output_units will be taken as the maximum number of time units to display in all output time duration values. By default, this is NULL and all possible time units will be displayed. This option has no effect when duration_style = "colon-sep" (only output_units can be used to customize that type of duration output).

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.

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.

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).

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. By default only negative values will display a minus sign.

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 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.

Value

An object of class gt_tbl.

Output units for the colon-separated duration style

The colon-separated duration style (enabled when duration_style = "colon-sep") is essentially a clock-based output format which uses the display logic of chronograph watch functionality. It will, by default, display duration values in the (D/)HH:MM:SS format. Any duration values greater than or equal to 24 hours will have the number of days prepended with an adjoining slash mark. While this output format is versatile, it can be changed somewhat with the output_units option. The following combinations of output units are permitted:

c("minutes", "seconds") -> MM:SS
c("hours", "minutes") -> HH:MM
c("hours", "minutes", "seconds") -> HH:MM:SS
c("days", "hours", "minutes") -> (D/)HH:MM

Any other specialized combinations will result in the default set being used, which is c("days", "hours", "minutes", "seconds")

Compatibility of formatting function with data values

The fmt_duration() formatting function is compatible with body cells that are of the "numeric", "integer", or "difftime" 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.

Targeting cells with `columns` and `rows`

Targeting of values is done through columns and additionally by rows (if nothing is provided for rows then entire columns are selected). The columns argument allows us to target a subset of cells contained in the resolved columns. We say resolved because aside from declaring column names in c() (with bare column names or names in quotes) we can use tidyselect-style expressions. This can be as basic as supplying a select helper like starts_with(), or, providing a more complex incantation like

where(~ is.numeric(.x) && max(.x, na.rm = TRUE) > 1E6)

which targets numeric columns that have a maximum value greater than 1,000,000 (excluding any NAs from consideration).

By default all columns and rows are selected (with the everything() defaults). Cell values that are incompatible with a given formatting function will be skipped over, like character values and numeric fmt_*() functions. So it's safe to select all columns with a particular formatting function (only those values that can be formatted will be formatted), but, you may not want that. One strategy is to format the bulk of cell values with one formatting function and then constrain the columns for later passes with other types of formatting (the last formatting done to a cell is what you get in the final output).

Once the columns are targeted, we may also target the rows within those columns. This can be done in a variety of ways. If a stub is present, then we potentially have row identifiers. Those can be used much like column names in the columns-targeting scenario. We can use simpler tidyselect-style expressions (the select helpers should work well here) and we can use quoted row identifiers in c(). It's also possible to use row indices (e.g., c(3, 5, 6)) though these index values must correspond to the row numbers of the input data (the indices won't necessarily match those of rearranged rows if row groups are present). One more type of expression is possible, an expression that takes column values (can involve any of the available columns in the table) and returns a logical vector. This is nice if you want to base formatting on values in the column or another column, or, you'd like to use a more complex predicate expression.

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 value be provided in sep_mark, it 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 use the info_locales() function to view an info table.

Examples

Use part of the sp500 table to create a gt table. Create a difftime-based column and format the duration values to be displayed as the number of days since March 30, 2020.

sp500 |>
  dplyr::slice_head(n = 10) |>
  dplyr::mutate(
    time_point = lubridate::ymd("2020-03-30"),
    time_passed = difftime(time_point, date)
  ) |>
  dplyr::select(time_passed, open, close) |>
  gt(rowname_col = "month") |>
  fmt_duration(
    columns = time_passed,
    output_units = "days",
    duration_style = "wide"
  ) |>
  fmt_currency(columns = c(open, close))

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

Function ID

3-16

Function Introduced

v0.7.0 (Aug 25, 2022)