Using relative path names . and

New to Julia
1

Hi! I m trying to list the regular files in the current or parent directory, to the exclusion of directories and subdirectories, using the relative paths “.” and “…”, with mixed results:

julia> pwd()
"/Users/michel/Codes/Julia/parent/child"

shell> ls
c_file1 c_file2

shell> ls ..
child  p_file

julia> filter(x -> isfile(x), readdir("."))
2-element Vector{String}:
 "c_file1"
 "c_file2"

julia> filter(x -> isfile(x), readdir(".."))
String[]

Why is this command working as expected with “.” but not returning the name of the file (p_file) in the parent directory “…”? Thanks for any clarification.

2

Because isfile is provided the filename of a file which is not in the current directory.

When you use readdir("..",join=true) it should work as the full path is passed to isfile.

3

@feanor12: Thanks for answering. Indeed:

julia> filter(x -> isfile(x), readdir(".."))
String[]

julia> filter(x -> isfile(x), readdir("..", join = true))
1-element Vector{String}:
 "../p_file"

and also

julia> filter(x -> isfile("../" * x), readdir(".."))
1-element Vector{String}:
 "p_file"
4

Or put another way,

filter(x -> isfile(x), readdir(d))

will only do what you expect if d is effectively the same as your current directory, e.g. "." or the absolute path to your current directory.

What you should do instead is either

filter(x -> isfile(joinpath(d, x)), readdir(d))

or

filter(x -> isfile(x), readdir(d, join = true))

depending on whether you want full paths in the result for further processing.

5

@GunnarFarneback: Great! Even better. Thanks a lot.

6

Note that

filter(x -> isfile(x), readdir(d, join = true))

can be simplified to

filter(isfile, readdir(d, join = true))
7

@sijo: Very interesting. I did not know this was even allowed… This being said, I’m also working on a Mac, which creates “hidden files” that I want to filter out too, like this:

filter(x -> isfile(joinpath(fpath, x)) && x != ".DS_Store", readdir(fpath, join = false)))

so I guess in need to keep the x notation in order to use it in the subsequent test… unless there is another trick to be learned!

Thanks for your input.