如何创建特定的文件夹/子文件夹树？

Question

I'm trying to create a very specific folder tree using Python that will create predefined folders and subfolders. I can create the top and second level folders, but the program messes up when it creates the third and fourth level folders. It either doesn't make these folders, or makes them in the incorrect places. I'm trying to use os.makedirs and can't figure out an easier way to do it than nested for loops which is messy and probably causing all of the problems.

import os

topLvl=["1", "2", "3"]
docSecLvl=["Info", "Reports"]
findSecLvl=["Ex", "In", "Ph"]
dataSecLvl=["DB", "Ph", "NM", "Test", "Vul", "App"]
phThrdLvl=["Template", "Payload"]
nm_vulsThrdLvl=["Ex", "In"]
ntmFrthLvl=["Nm", "Eye"]
vulsFrthLvl=["NS"]
appThrdLvl=["2", "3"]

def main():
    for dir1 in topLvl:
        if dir1=="1":
            for dir2 in docSecLvl:
                dirmake(dir1, dir2)
        if dir1=="2":
            for dir2 in findSecLvl:
                dirmake(dir1, dir2)
        if dir1=="3":
            for dir2 in dataSecLvl:
                dirmake(dir1, dir2)

            if dir2=="Ph":
                for dir3 in phThrdLvl:
                    dirmake(dir2, dir3)

            if dir2=="NM":
                for dir3 in nm_vulsThrdLvl:
                    dirmake(dir2, dir3)

                if dir3=="Ex":
                    for dir4 in ntmFrthLvl: 
                        dirmake(dir3, dir4)

                if dir3=="In":
                    for dir4 in ntmFrthLvl: 
                        dirmake(dir3, dir4)

            if dir2=="Vul":
                for dir3 in nm_vulsThrdLvl:
                    dirmake(dir2, dir3)

                if dir3=="Ex":
                    for dir4 in vulFrthLvl: 
                        dirmake(dir3, dir4)

                if dir3=="In":
                    for dir4 in vulFrthLvl: 
                        dirmake(dir3, dir4)

            if dir2=="App":
                for dir3 in appThrdLvl:
                    dirmake(dir2, dir3)



    def dirmake(d1, d2):
        try: os.makedirs(os.path.join(d1, d2))
        except OSError: pass

    main()

Answer 1

Well, the foremost problem with the existing code is that it just joins two directory names to make a path, so for instance "App" and "2" is made into the path "App/2" instead of "3/App/2", as it should be.

Also, using makedirs() is slightly dangerous, as it will make all intermediate directories, even if they are wrong for some reason and don't exist. And the existing code demonstrates that nicely, as it will make two levels deep of wrong directories without failing.

I would suggest representing the tree to create with the help of nested dictionaries, like that:

NTM_FOURTH_LEVEL = {
    "Nm": {},
    "Eye": {},
}

VULS_FOURTH_LEVEL = {
    "NS": {},
}

DIRECTORY_STRUCTURE = {
    "1": {
        "Info": {},
        "Reports": {},
    },
    "2": {
        "Ex": {},
        "In": {},
        "Ph": {},
    },
    "3": {
        "DB": {},
        "Ph": {
            "Template": {},
            "Payload": {},
        },
        "NM": {
            "Ex": NTM_FOURTH_LEVEL,
            "In": NTM_FOURTH_LEVEL,
        },
        "Vul": {
            "Ex": VULS_FOURTH_LEVEL,
            "In": VULS_FOURTH_LEVEL,
        },
        "App": {
            "2": {},
            "3": {},
        },
    },
}

And then you can use a small and elegant recursive function to create the actual directory tree:

import os
import os.path


def make_dir_tree(tree, prefix=''):
    for name, subtree in tree.items():
        path = os.path.join(prefix, name)
        os.mkdir(path)
        make_dir_tree(subtree, prefix=path)


def main():
    make_dir_tree(DIRECTORY_STRUCTURE)


if __name__ == '__main__':
    main()

As an extra that comes for free, you can use the prefix parameter to create the tree under some directory you specify instead of the current directory:

make_dir_tree(DIRECTORY_STRUCTURE, prefix="somewhere/deeper")
make_dir_tree(DIRECTORY_STRUCTURE, prefix="/absolute/path")