Given the names of (potential) directories, create the ones that do not already exist.
create_dir(...)
The names of the directories, specified via relative or absolute paths. Duplicates are ignored.
Invisibly, a vector with a TRUE
for each time a directory was
actually created and a FALSE
otherwise. This vector is named with the
paths of the directories that were passed to the function.
if (FALSE) {
create_dir(c("mydir", "yourdir"))
remove_dir(c("mydir", "yourdir"))
}