Question

我有一个大字典，我想删除某些键。我定义了一组不需要的键，假设它叫做kunwanted。字典看起来像这样：

   mydic= {'user':{'key1':'12','key2':'20','key3':30},
          'status':{'newk':'12','user':{'key1':'12','key2':'20','key3':30}}}

所以，我将关键'用户'作为mydic的关键，并作为mydic ['status']的关键。让我们说在kunwanted我有'key1'和'key2'。显然，我可以通过mydic迭代2次以删除元素：

for elem in kunwanted:
    if elem in mydic['status']['user']:
        del mydic['status']['user'][elem]

for elem in kunwanted:
    if elem in mydic['user']:
        del mydic['user'][elem]

有更有效的方法来实现这个目标吗？

Answer 1

这是一种递归方法：

#!/usr/local/cpython-3.3/bin/python

import pprint

def recursive_remover(unwanted_keys, dictionary):
    for key, value in list(dictionary.items()):
        if isinstance(value, dict):
            recursive_remover(unwanted_keys, value)

        if key in unwanted_keys:
            del dictionary[key]

def main():
    mydict={'user': {'key1':'12','key2':'20','key3':30},
           'status':{'newk':'12','user':{'key1':'12','key2':'20','key3':30}}}

    unwanted_keys = { 'key1', 'key2' }

    recursive_remover(unwanted_keys, mydict)

    pprint.pprint(mydict)

main()

Answer 2

我不确定我是否采用了正确的方式，以下可能会有所帮助

for elem in kunwanted:
    if elem in mydic['user']:
        del mydic['user'][elem]
        break #
    if elem in mydic['status']['user']:
        del mydic['status']['user'][elem]

Answer 3

另一种递归方法。

def recursive_remove(u_keys, d):
    # Remove keys in current dict
    for unwanted_key in u_keys:
        try:
            del d[unwanted_key]
        except (KeyError, TypeError):
            continue
    # Try to iterate over the items in dict, continue if not iterable
    for key, value in d.iteritems():
        try:
            recursive_remove(u_keys, value)
        except AttributeError:
            continue


my_dict= {'user':{'key1':'12','key2':'20','key3':30},
          'status':{'newk':'12','user':{'key1':'12','key2':'20','key3':30}}}

u_keys = ['key1', 'key2']

recursive_remove(u_keys, my_dict)

Answer 4

将其压缩为单个for循环应该会略微加快执行速度。

for elem in kunwanted:
    if elem in mydict['status']['user']:
        del mydic['status']['user'][elem]
    if elem in mydic['user']:
        del mydic['user'][elem]

从嵌套字典中删除多个键

4 个答案: