pillar: new_pillar_shaft – R documentation

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new_pillar_shaft

Constructor for column data

Description

The new_pillar_shaft() constructor creates objects of the "pillar_shaft" class. This is a virtual or abstract class, you must specify the class argument. By convention, this should be a string that starts with "pillar_shaft_". See vignette("extending", package = "tibble") for usage examples.

This method accepts a vector of arbitrary length and is expected to return an S3 object with the following properties:

It has an attribute "width"
It can have an attribute "min_width", if missing, "width" is used
It must implement a method format(x, width, ...) that can be called with any value between min_width and width
This method must return an object that inherits from character and has attributes "align" (with supported values "left", "right", and "center") and "width"

The function new_pillar_shaft() returns such an object, and also correctly formats NA values. In many cases, the implementation of pillar_shaft.your_class_name() will format the data as a character vector (using color for emphasis) and simply call new_pillar_shaft(). See pillar:::pillar_shaft.numeric for a code that allows changing the display depending on the available width.

new_pillar_shaft_simple() provides an implementation of the pillar_shaft class suitable for output that has a fixed formatting, which will be truncated with a continuation character (ellipsis or ~) if it doesn't fit the available width. By default, the required width is computed from the natural width of the formatted argument.

Usage

new_pillar_shaft(
  x,
  ...,
  width = NULL,
  min_width = width,
  class = NULL,
  subclass = NULL
)

new_pillar_shaft_simple(
  formatted,
  ...,
  width = NULL,
  align = "left",
  min_width = NULL,
  na = NULL,
  na_indent = 0L,
  shorten = c("back", "front", "mid", "abbreviate")
)

Arguments

`x`	An object
`...`	Additional attributes.
`width`	The maximum column width.
`min_width`	The minimum allowed column width, `width` if omitted.
`class`	The name of the subclass.
`subclass`	Deprecated, pass the `class` argument instead.
`formatted`	An object coercible to character.
`align`	Alignment of the column.
`na`	String to use as `NA` value, defaults to `"NA"` styled with `style_na()` with fallback if color is not available.
`na_indent`	Indentation of `NA` values.
`shorten`	How to abbreviate the data if necessary: `"back"` (default): add an ellipsis at the end `"front"`: add an ellipsis at the front `"mid"`: add an ellipsis in the middle `"abbreviate"`: use `abbreviate()`

Details

The formatted argument may also contain ANSI escapes to change color or other attributes of the text, see crayon.

pillar

Coloured Formatting for Columns

v1.6.0

MIT + file LICENSE

Authors

Kirill Müller [aut, cre], Hadley Wickham [aut], RStudio [cph]

Initial release