python - 如何将一些数据添加到 python 字典中的特定 'path'？

Question

比如我要定义一个函数:

def add_value(dic, path, value):
    # dict is a Dictionary to be modified
    # path is a list, like ['A', 'B', 'C', ...]
    # value is a list or tuple
    ...
    ...
    return dic


d = {}
d = add_value(d, ['A', 'B'], ('log.txt', '12KB'))
print(d)
d = add_value(d, ['X', 'Y', 'Z'], ('backup.bin', '17MB'))
print(d)
d = add_value(d, ['X', 'Y', 'Z'], ('file.lst', '5KB'))
print(d)

接下来的输出应该是这样的:

{'A': {'B': {'log.txt': '12KB'}}}

{'A': {'B': {'log.txt': '12KB'}}, 'X': {'Y': {'Z': {'backup.bin': '17MB'}}}}

{'A': {'B': {'log.txt':'12KB'}}, 'X': {'Y': {'Z': {'backup.bin': '17MB', 'file.lst': '5KB'}}}}

我试过这样的:

import json
def add_value(dic, path, value):
    # dic is a dict to be modified
    # path is a list
    # value is a tumple like ('file1.txt': '20kb')
    length = len(path)
    if length == 1:
        if path[0] not in dic:
            dic[path[0]] = {}
        else:
            dic[path[0]].append(value)
            return dic
    elif length == 2:
        if path[0] not in dic:
            dic[path[0]] = {}
        if path[1] not in dic[path[0]]:
            dic[path[0]][path[1]] = {}
        dic[path[0]][path[1]][value[0]] = value[1]
        return dic
    elif length == 3:
        if path[0] not in dic:
            dic[path[0]] = {}
        if path[1] not in dic[path[0]]:
            dic[path[0]][path[1]] = {}
        if path[2] not in dic[path[0]][path[1]]:
            dic[path[0]][path[1]][path[2]] = {}
        dic[path[0]][path[1]][path[2]][value[0]] = value[1]
        return dic
    elif length == 4:
        if path[0] not in dic:
            dic[path[0]] = {}
        if path[1] not in dic[path[0]]:
            dic[path[0]][path[1]] = {}
        if path[2] not in dic[path[0]][path[1]]:
            dic[path[0]][path[1]][path[2]] = {}
        if path[3] not in dic[path[0]][path[1]][path[2]]:
            dic[path[0]][path[1]][path[2]][path[3]] = {}
        dic[path[0]][path[1]][path[2]][path[3]][value[0]] = value[1]
        return dic
    else:
        return



d = {}
d = add_value(d, ['A', 'B'], ('log.txt', '12KB'))
d = add_value(d, ['A', 'B', 'C',], ('log2.txt', '34kb'))
d = add_value(d, ['A', 'G'], ('log2.txt', '2kb'))
d = add_value(d, ['X', 'Y', 'Z'], ('log2.txt', '3kb'))
print(json.dumps(d, indent=2))

输出是:

{   "X": {
    "Y": {
      "Z": {
        "log2.txt": "3kb"
      }
    }   },   "A": {
    "G": {
      "log2.txt": "2kb"
    },
    "B": {
      "C": {
        "log2.txt": "34kb"
      },
      "log.txt": "12KB"
    }   } }

看起来很蠢。如果我想 add_value(d, ['A', 'B', 'C', ... , 'Y', 'Z'], ('1.jpg', '1.2MB')) ，我需要编写大量代码。

Answer 1

你可以使用这个:

def add_value(d, path, value):
    curr = d
    for key in path:
        if key not in curr:
            curr[key] = {}
        curr = curr[key]
    k, v = value
    curr[k] = v

    return d

d = {}
d = add_value(d, ['A', 'B'], ('log.txt', '12KB'))
print(d)
d = add_value(d, ['X', 'Y', 'Z'], ('backup.bin', '17MB'))
print(d)
d = add_value(d, ['X', 'Y', 'Z'], ('file.lst', '5KB'))
print(d)

输出:

{'A': {'B': {'log.txt': '12KB'}}}
{'A': {'B': {'log.txt': '12KB'}}, 'X': {'Y': {'Z': {'backup.bin': '17MB'}}}}
{'A': {'B': {'log.txt': '12KB'}}, 'X': {'Y': {'Z': {'backup.bin': '17MB', 'file.lst': '5KB'}}}}

该函数将检查当前键是否已存在于字典中。如果它不存在，它将创建一个新的键，并将一个空字典作为值。