empty-methods: Identify empty interval rows

In edzer/intervals: Tools for Working with Points and Intervals

Identify empty interval rows

Description

A valid interval matrix may contain empty intervals: those with common endpoints, at least one of which is open. The empty method identifies these rows.

Usage

## S4 method for signature 'Intervals'
empty(x)

## S4 method for signature 'Intervals_full'
empty(x)

Arguments

x	An "Intervals" or "Intervals_full" object.

Details

Intervals are deemed to be empty when their endpoints are equal and not both closed, or for type == "Z", when their endpoints differ by 1 and both are open. The matrices x and x[!empty(x),] represent the same subset of the integers or the real line.

Value

A boolean vector with length equal to nrow(x).

Warning

Exact equality (==) comparisons are used by empty. See the package vignette for a discussion of equality and floating point numbers.

Note

Note that intervals of size 0 may not be empty over the reals, and intervals whose second endpoint is strictly greater than the first may be empty over the integers, if both endpoints are open.

See Also

See size to compute the size of each interval in an object.

Examples

z1 <- Intervals( cbind( 1, 1:3 ), type = "Z" )
z2 <- z1; closed(z2)[1] <- FALSE
z3 <- z1; closed(z3) <- FALSE

empty(z1)
empty(z2)
empty(z3)

r1 <- z1; type(r1) <- "R"
r2 <- z2; type(r2) <- "R"
r3 <- z3; type(r3) <- "R"

empty(r1)
empty(r2)
empty(r3)

s1 <- Intervals_full( matrix( 1, 3, 2 ), type = "Z" )
closed(s1)[2,2] <- FALSE
closed(s1)[3,] <- FALSE

empty(s1)

edzer/intervals documentation built on Sept. 8, 2023, 9:12 p.m.