使用应用函数dir.exist和dir.create

Question

I am trying to use a vector of characters to create a series of directories in my working directory. Nothing recursive, simply iterative. Nothing fancy. as an example, I can do this pretty easily with:

lapply(state.name, dir.create)

which creates 50 directories of all US states in my working directory. I can easily delete them if I want using:

unlink(state.name)

However, what I would really like to do is test to see if any of the directories exist already, and then create the ones that are not already there. I have found similar questions here: Check existence of directory and create if doesn't exist but everything I have found on Stack Exchange and through other Google searches either take a deep dive into the apply family of functions, or explain how to create a single directory in R. The recursive checking and creating I would like to do does not seem to exist. I have come up with the following, and it works, sort of, but it is really only checking the first entry in the vector.

if(!file.exists(state.name)) {lapply(state.name, dir.create)}

If I try to use the lapply function with file.exists, it throws an error.

Any help is greatly appreciated. Thank you.

Answer 1

lapply(state.name, function(x) if(!dir.exists(x)) dir.create(x))

Answer 2

lapply(state.name[!state.name %in% dir()], dir.create)