ansi_collapse: Collapse a vector into a string scalar

In r-lib/boxes: Helpers for Developing Command Line Interfaces

Collapse a vector into a string scalar

Description

Features:

• custom separator (sep),

• custom separator for length-two input (sep2),

• custom last separator (last),

• adds ellipsis to truncated strings,

• uses Unicode ellipsis character on UTF-8 console,

• can collapse "from both ends", with style = "both-ends",

• can consider a limit for the display width of the result, in characters,

• handles ANSI control sequences correctly when measuring display width.

Usage

ansi_collapse(
  x,
  sep = ", ",
  sep2 = " and ",
  last = ", and ",
  trunc = Inf,
  width = Inf,
  ellipsis = symbol$ellipsis,
  style = c("both-ends", "head")
)

Arguments

x	Character vector, or an object with an as.character() method to collapse.
sep	Separator. A character string.
sep2	Separator for the special case that x contains only two elements. A character string.
last	Last separator, if there is no truncation. E.g. use ", and " for the serial comma. A character string.
trunc	Maximum number of elements to show. For style = "head" at least trunc = 1 is used. For style = "both-ends" at least trunc = 5 is used, even if a smaller number is specified.
width	Limit for the display width of the result, in characters. This is a hard limit, and the output will never exceed it. This argument is not implemented for the "both-ends" style, which always uses Inf, with a warning if a finite width value is set.
ellipsis	Character string to use at the place of the truncation. By default, the Unicode ellipsis character is used if the console is UTF-8, and three dots otherwise.
style	Truncation style: both-ends: the default, shows the beginning and end of the vector, and skips elements in the middle if needed. head: shows the beginning of the vector, and skips elements at the end, if needed.

Value

Character scalar. It is NA_character_ if any elements in x are NA.

See Also

glue_collapse in the glue package inspired this function.

Examples

ansi_collapse(letters)

# truncate
ansi_collapse(letters, trunc = 5)

# head style
ansi_collapse(letters, trunc = 5, style = "head")

r-lib/boxes documentation built on April 24, 2024, 11:37 a.m.