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Test for sinks in a numeric series

Source: R/has_sink.R
has_sink.Rd

has_sink_in() tests whether a numeric series has a sink in the interval [from, to]. has_sink_at() tests whether there is a sink at a given value, optionally with a specific direction.

Usage

has_sink_in(x, from = -Inf, to = Inf)

has_sink_at(x, value, dir = c("either", "left", "right", "both"))

Arguments

x

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

from, to

Reference values, possibly infinite. from must be less than or equal to to; both must be length-1 numeric vectors.

value

Single numeric to check for the existence of a sink.

dir

Single character: direction of the sink. "either" (default) ignores direction; "left" or "right" require the sink to be approached from that side; "both" requires it to be approached from both sides.

Value

A length-one logical: TRUE if a sink exists in the range (has_sink_in) or at value with the given dir (has_sink_at); FALSE otherwise.

See also

See sinks() to get all sinks, and a description of sinks.

Examples

# The set of integers have sinks at +Inf and -Inf
has_sink_in(integers())
#> [1] TRUE
has_sink_at(integers(), Inf)
#> [1] TRUE
has_sink_at(integers(), -Inf, dir = "right")
#> [1] TRUE

# The set 1, 1/2, 1/4, 1/8, ... has a sink at 0 approached from the right.
halves <- 0.5^natural0()
has_sink_in(halves, to = 0)
#> [1] FALSE
has_sink_at(halves, 0, dir = "right")
#> [1] TRUE

# Reciprocal of integers: sink at 0 from both sides
reciprocals <- 1 / integers()
has_sink_at(reciprocals, 0, dir = "both")
#> [1] TRUE