unwhich: Quasi-inverse of the 'which' function
In bazar: Miscellaneous Basic Functions

Description Usage Arguments Value See Also Examples

The unwhich function is a kind of inverse of the which function.

1	unwhich(w, n)

`w`	A vector of integers; morally the result of a call to `which`.
`n`	integer. The length of the result; morally the length of the `x` argument of a call to `which`.

A logical vector of length n.

which.

x1 <- c(TRUE, FALSE, TRUE, TRUE)
x2 <- unwhich(which(x1), length(x1))
identical(x1, x2) # TRUE

w1 <- c(2, 4, 5, 1, 1)
w2 <- which(unwhich(w1, 10))
identical(sort(unique(as.integer(w1))), w2) # TRUE