Set a column format with a formatter function

The fmt() function provides greater control in formatting raw data values than any of the specialized fmt_*() functions that are available in gt. Along with the columns and rows arguments that provide some precision in targeting data cells, the fns argument allows you to define one or more functions for manipulating the raw data.

If providing a single function to fns, the recommended format is in the form: fns = function(x) .... This single function will format the targeted data cells the same way regardless of the output format (e.g., HTML, LaTeX, RTF).

If you require formatting of x that depends on the output format, a list of functions can be provided for the html, latex, and default contexts. This can be in the form of fns = list(html = function(x) ..., latex = function(x) ..., default = function(x) ...). In this multiple-function case, we recommended including the default function as a fallback if all contexts aren't provided.

fmt(data, columns = everything(), rows = everything(), fns)

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 c(), 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(), num_range(), and everything().
rows	Optional rows to format. Providing either everything() (the default) or TRUE results in all rows in columns being formatted. Can either be a vector of row captions provided in 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(), 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).
fns	Either a single formatting function or a named list of functions.

Value

An object of class gt_tbl.

Details

As with all of the fmt_*() functions, targeting of values is done through columns and additionally by rows (if nothing is provided for rows then entire columns are selected). Conditional formatting is possible by providing a conditional expression to the rows argument. See the Arguments section for more information on this.

Figures

Function ID

3-14

See also

Other Format Data: data_color(), fmt_bytes(), fmt_currency(), fmt_datetime(), fmt_date(), fmt_engineering(), fmt_integer(), fmt_markdown(), fmt_missing(), fmt_number(), fmt_passthrough(), fmt_percent(), fmt_scientific(), fmt_time(), text_transform()

Examples

# Use `exibble` to create a gt table;
# format the numeric values in the `num`
# column with a function supplied to
# the `fns` argument
tab_1 <-
  exibble %>%
  dplyr::select(-row, -group) %>%
  gt() %>%
  fmt(
    columns = num,
    fns = function(x) {
      paste0("'", x * 1000, "'")
    }
  )