match_file.Rd
Return a list of files given a full prefix and optional suffix. Optionally, confirm that the right number of files are returned. If the wrong number of files is returned, throw an error.
match_file(path_prefix, suffix = NULL, expect = NULL)
Character vector of matched file names, as full paths.
If path_prefix
points to a directory, then all files inside that directory
that match the suffix (if provided) are returned.