convert directory-tree like strings into nested list data structure python

Question

I have a list of 'directory-tree-like' strings. I want to convert it into a nested list (or another kind of data structure), to emphasize the dependencies. for example, the input:

hierarchy_list

dir1
dir1/dir1.1                                            
dir1/dir1.2
dir1/dir1.3/dir1.3.1/dir1.3.1.1
dir1/dir1.1/dir1.1.1
dir1/dir1.1/dir1.1.2

need to be converted to:

dir1 ->
    dir1.1 -> dir1.1.1 , dir1.1.2
    dir1.2
    dir1.3 -> dir1.3.1 , dir1.3.2

where the '->' symbolize 'contains' (in a form of array attribute or equivalent).

dir1 contains list of dir1.1 , 1.2 , 1.3

dir1.1 contains list of dir1.1.1 , dir1.1.2

and so on...

Does someone have an idea how to do it in Python (algorithm and implementation)?

Stephen Rauch · Accepted Answer · 2018-05-13 17:57:53Z

2

With a bit of recursion and a dict that can be done like:

Code:

def build_dir_dict(dir_name_strings):

    def _build_dir_dict(path_pieces, dir_dict):
        print(path_pieces)
        if path_pieces:
            if not path_pieces[0]:
                _build_dir_dict(path_pieces[1:], dir_dict)
            else:
                if path_pieces[0] not in dir_dict:
                    dir_dict[path_pieces[0]] = {}
                _build_dir_dict(path_pieces[1:], dir_dict[path_pieces[0]])

    result = {}
    for dir_name_string in dir_name_strings:
        if dir_name_string:
            _build_dir_dict(dir_name_string.split('/'), result)
    return result

Test Code:

data = [x.strip() for x in """
    dir1 
    dir1/dir1.1
    dir1/dir1.2 
    dir1/dir1.3/dir1.3.1/dir1.3.1.1 
    dir1/dir1.1/dir1.1.1 
    dir1/dir1.1/dir1.1.2
""".split('\n')[1:-1]]

print(build_dir_dict(data))

Results:

{'dir1': {'dir1.1': {'dir1.1.1': {}, 'dir1.1.2': {}}, 
          'dir1.2': {}, 
          'dir1.3': {'dir1.3.1': {'dir1.3.1.1': {}}}
    }
}

answered May 13, 2018 at 17:57

Stephen Rauch♦

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1 Comment

Manor Zvi Over a year ago

THANK YOU! that looks really sweet solution. I had a thought about recursion, but it stayed in the back part of my head...

Mark · Accepted Answer · 2018-05-13 18:06:05Z

1

For each path, you can just split() it on the '/', then loop through them adding to an existing key or creating the key as needed and then assigning that to the current parent to be considered next. For example:

arr= ['dir1','dir1/dir1.1','dir1/dir1.2','dir1/dir1.3/dir1.3.1/dir1.3.1.1', 'dir1/dir1.1/dir1.1.1','dir1/dir1.1/dir1.1.2']

d = dict()
for path in arr:
    parent = d
    for dir in path.split('/'):    
        if dir not in parent:
            parent[dir] = dict()
        parent = parent[dir]

The result d will look like:

{'dir1': {'dir1.1': {'dir1.1.1': {}, 'dir1.1.2': {}},
          'dir1.2': {},
          'dir1.3': {'dir1.3.1': {'dir1.3.1.1': {}}}
          }
}

answered May 13, 2018 at 18:06

Mark

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1 Comment

Manor Zvi Over a year ago

thanks, man! the thing is that I don't know how depth can be the hierarchy... look for the recursive solution above

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