checkmate (version 1.7.2)

wf: Get the index of the first/last TRUE

Description

A quick C implementation for which.first (head(which(x), 1)) and which.last (tail(which(x), 1)).

Usage

wf(x, use.names = TRUE)
wl(x, use.names = TRUE)

Arguments

x

[logical] Logical vector.

use.names

[logical(1)] If TRUE and x is named, the result is also named.

Value

• [integer(1) | integer(0)]. Returns the index of the first/last TRUE value in x or an empty integer vector if none is found. NAs are ignored.

Examples

wf(c(FALSE, TRUE))
wl(c(FALSE, FALSE))
wf(NA)