Find the positions of first or last occurrence of unique vector elements

This function finds the positions of first or last occurrence of unique vector elements.

Usage

vector_occurrence(x, type = "first")

Arguments

x

[atomic()]
A vector.

type

[character(1)]
Either "first" for the first or "last" for the last occurrence.

Value

An integer vector, the positions of the unique vector elements. The ordering corresponds to unique(x), i.e., the \(i\)-th element in the output is the (first or last) occurrence of the \(i\)-th element from unique(x).

See also

Other vector helpers: check_numeric_vector(), check_probability_vector(), chunk_vector(), equidistant_vectors(), insert_vector_entry(), map_indices(), match_numerics(), permutations(), split_vector_at(), subsets()

Examples

x <- c(1, 1, 1, 2, 2, 2, 3, 3, 3)
unique(x)
#> [1] 1 2 3
vector_occurrence(x, "first")
#> [1] 1 4 7
vector_occurrence(x, "last")
#> [1] 3 6 9