Set a column format with a formatter function

fmt() provides a way to execute custom formatting functionality with raw data values in a way that can consider all output contexts.

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, rtf, 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.

Usage

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

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).

compat

Formatting compatibility

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

An optional vector that provides the compatible classes for the formatting. By default this is NULL.

fns

Formatting functions

function|list of functions // required

Either a single formatting function or a named list of functions. Can also be anonymous functions, in both base R (\(x) x + 1) and rlang (~.x + 1) syntax.

Value

An object of class gt_tbl.

Examples

Use the exibble dataset to create a gt table. We'll format the numeric values in the num column with fmt(). We supply a functions to the fns argument. This supplied function will take values in the column (x), multiply them by 1000, and exclose them in single quotes.

exibble |>
  dplyr::select(-row, -group) |>
  gt() |>
  fmt(
    columns = num,
    fns = function(x) {
      paste0("'", x * 1000, "'")
    }
  )

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

Function ID

3-30

Function Introduced

v0.2.0.5 (March 31, 2020)