First candidate path that exists

Returns the first element of `candidates` for which [dir.exists()] is `TRUE`. If none exist but one has a parent directory that exists, creates that candidate and returns it. Errors if none of the candidates or their parents exist.

Usage

first_existing_path(candidates, label = NULL)

Arguments

candidates

Character vector of candidate paths, in priority order.

label

Optional label used in error messages to describe what kind of path is being resolved (e.g. `"data_rawbatch_dir"`).

Value

A single character path: the first candidate that exists, or a newly-created one.

Details

This is the stateless primitive used by [CandidatePath] for resolution. Scripts that just need "give me the first of these paths that exists" can call it directly.

See also

[CandidatePath] for the stateful, caching wrapper used by the R6 classes in this package; [invalidate_candidate_paths()] for the save-time cache clearer that makes objects portable across hosts.

Other multi_host_paths: CandidatePath, invalidate_candidate_paths()

Examples

d <- tempfile()
dir.create(d)
first_existing_path(c("/definitely/not/there", d))
#> [1] "/tmp/RtmpoyXnmG/file1dc8284a6139"