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Label discrete data

Source: R/labels.R
lbl_discrete.Rd

lbl_discrete() creates labels for discrete data, such as integers. For example, breaks c(1, 3, 4, 6, 7) are labelled: "1-2", "3", "4-5", "6-7".

Usage

lbl_discrete(
  symbol = em_dash(),
  unit = 1,
  fmt = NULL,
  single = NULL,
  first = NULL,
  last = NULL
)

Arguments

symbol

String: symbol to use for the dash.

unit

Minimum difference between distinct values of data. For integers, 1.

fmt

String, list or function. A format for break endpoints.

single

Glue string: label for singleton intervals. See lbl_glue() for details.

first

Glue string: override label for the first category. Write e.g. first = "<{r}" to create a label like "<18". See lbl_glue() for details.

last

String: override label for the last category. Write e.g. last = ">{l}" to create a label like ">65". See lbl_glue() for details.

Value

A function that creates a vector of labels.

Details

No check is done that the data are discrete-valued. If they are not, then these labels may be misleading. Here, discrete-valued means that if x < y, then x <= y - unit.

Be aware that Date objects may have non-integer values. See Date.

Formatting endpoints

If fmt is not NULL then it is used to format the endpoints.

  • If fmt is a string, then numeric endpoints will be formatted by sprintf(fmt, breaks); other endpoints, e.g. Date objects, will be formatted by format(breaks, fmt).

  • If fmt is a list, then it will be used as arguments to format.

  • If fmt is a function, it should take a vector of numbers (or other objects that can be used as breaks) and return a character vector. It may be helpful to use functions from the {scales} package, e.g. scales::label_comma().

See also

Other labelling functions: lbl_dash(), lbl_endpoints(), lbl_glue(), lbl_intervals(), lbl_manual(), lbl_midpoints(), lbl_seq()

Examples

tab(1:7, c(1, 3, 5), lbl_discrete())
#> 1—2 3—4 5—7 
#>   2   2   3 

tab(1:7, c(3, 5), lbl_discrete(first = "<= {r}"))
#> <= 2  3—4  5—7 
#>    2    2    3 

tab(1:7 * 1000, c(1, 3, 5) * 1000, lbl_discrete(unit = 1000))
#> 1000—2000 3000—4000 5000—7000 
#>         2         2         3 

# Misleading labels for non-integer data
chop(2.5, c(1, 3, 5), lbl_discrete())
#> [1] 1—2
#> Levels: 1—2