python - 通过键列表从嵌套的 python 字典中删除键

Question

我有一个嵌套字典，即

a={'k1':{'k2':1}}

我想写一个函数

def f(dictionary,key_list):
      pass

f(a,['k1','k2']) 等价于 del(a['k1']['k2'])

我试过

from functools import reduce
import operator

def f(dictionary,key_list):
     reduce(operator.delitem,key_list,dictionary)

不过

f(a,['k1','k2'])

返回

TypeError: 'NoneType' object does not support item deletion

Answer 1

你只想从最里面的字典中删除，而不是从外面的字典中删除。因此，对于到达最内层字典的路径，您需要使用 getitem，而不是 delitem。只应使用最后一个 key 进行删除:

def f(dictionary, key_list):
    *path, key = key_list
    del reduce(operator.getitem, path, dictionary)[key]

Demo(多一层更清晰):

from functools import reduce
import operator

def f(dictionary, key_list):
    *path, key = key_list
    del reduce(operator.getitem, path, dictionary)[key]

a = {'k1': {'k2': {'k3': 1}}}
f(a, ['k1', 'k2', 'k3'])
print(a)

打印 {'k1': {'k2': {}}}，与 del a['k1']['k2']['k3'] 之后相同:

a = {'k1': {'k2': {'k3': 1}}}
del a['k1']['k2']['k3']
print(a)