Traversing a numeric series

next_discrete() and prev_discrete() find the n discrete values in a numeric series next to a reference point. num_discretes() finds the number of discrete values within a range.

Usage

next_discrete(
  x,
  from,
  ...,
  n = 1L,
  include_from = FALSE,
  tol = sqrt(.Machine$double.eps)
)

prev_discrete(
  x,
  from,
  ...,
  n = 1L,
  include_from = FALSE,
  tol = sqrt(.Machine$double.eps)
)

Arguments

x

Numeric series (numeric vector or object of class "discretes").

from

Reference value to start searching from; single numeric.

...

Reserved for future extensions; must be empty.

n

Number of discrete values to find; single positive integer.

include_from

Should the from value be included in the query? Single logical; defaults to TRUE.

tol

Numerical tolerance when checking if a value is in the series. Single non-negative numeric. See next_discrete() for details.

Value

A vector of sequential points starting from from, which is included in the vector if it is a discrete value in the numeric series and include_from = TRUE. The length of the vector is at most n, and will return an empty numeric vector if there is no such discrete value. next_discrete() is increasing, while prev_discrete() is decreasing, so that earlier values are encountered sooner.

Details

For a transformed or combined series (e.g. 1 / integers()), traversal is delegated to the base series, and tol is passed through to those calls. This means that tol is only realized on the underlying series:

• Numeric vector (or as_discretes(...)): a value is a member if it is within tol of a stored value.

• Arithmetic series: the implied step index (distance from the representative in steps) is treated as an integer if it is within tol of an integer. See the Tolerance vignette for examples.

Examples

x <- integers(from = 2)
next_discrete(x, from = 1.3)
#> [1] 2
prev_discrete(x, from = 4, n = 10)
#> [1] 3 2
next_discrete(x - 0.7, from = 1.3, n = 4)
#> [1] 2.3 3.3 4.3 5.3