Python - 嵌套字典中的反转

给定一个嵌套字典，执行键的反转，即最内层嵌套变为最外层，反之亦然。

Input : test_dict = {“a” : {“b” : {}},
“d” : {“e” : {}},
“f” : {“g” : {}}
Output : {‘b’: {‘a’: {}}, ‘e’: {‘d’: {}}, ‘g’: {‘f’: {}}
Explanation : Nested dictionaries inverted as outer dictionary keys and viz-a-vis.

Input : test_dict = {“a” : {“b” : { “c” : {}}}}
Output : {‘c’: {‘b’: {‘a’: {}}}}
Explanation : Just a single key, mapping inverted till depth.

方法：使用循环+递归

这是可以执行此任务的粗暴方式。在此，我们使用递归提取每个键从外部到内部的所有路径，然后使用它来反转结果中的排序。

Python3

# Python3 code to demonstrate working of 
# Inversion in nested dictionary
# Using loop + recursion
  
# utility function to get all paths till end 
def extract_path(test_dict, path_way):
    if not test_dict:
        return [path_way]
    temp = []
    for key in test_dict:
        temp.extend(extract_path(test_dict[key], path_way + [key]))
    return temp
  
# function to compute inversion
def hlper_fnc(test_dict):
    all_paths = extract_path(test_dict, [])
    res = {}
    for path in all_paths:
        front = res
        for ele in path[::-1]:
            if ele not in front :
                front[ele] = {}
            front = front[ele]
    return res
  
# initializing dictionary
test_dict = {"a" : {"b" : {"c" : {}}},
             "d" : {"e" : {}},
             "f" : {"g" : {"h" : {}}}}
  
# printing original dictionary
print("The original dictionary is : " + str(test_dict))
  
# calling helper function for task 
res = hlper_fnc(test_dict)
  
# printing result 
print("The inverted dictionary : " + str(res))

输出

The original dictionary is : {'a': {'b': {'c': {}}}, 'd': {'e': {}}, 'f': {'g': {'h': {}}}}
The inverted dictionary : {'c': {'b': {'a': {}}}, 'e': {'d': {}}, 'h': {'g': {'f': {}}}}