Python：将 defaultdict 转换为 dict
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/20428636/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
Python: convert defaultdict to dict
提问by user2988464
How can i convert a defaultdict
我如何转换 defaultdict
number_to_letter
defaultdict(<class 'list'>, {'2': ['a'], '3': ['b'], '1': ['b', 'a']})
to be a common dict?
成为一个共同的字典？
{'2': ['a'], '3': ['b'], '1': ['b', 'a']}
采纳答案by DSM
You can simply call dict:
您可以简单地调用dict：
>>> a
defaultdict(<type 'list'>, {'1': ['b', 'a'], '3': ['b'], '2': ['a']})
>>> dict(a)
{'1': ['b', 'a'], '3': ['b'], '2': ['a']}
but remember that a defaultdict isa dict:
但请记住，defaultdict是一个 dict：
>>> isinstance(a, dict)
True
just with slightly different behaviour, in that when you try access a key which is missing -- which would ordinarily raise a KeyError-- the default_factoryis called instead:
只是行为略有不同，因为当您尝试访问丢失的密钥时——这通常会引发一个KeyError——default_factory而是调用：
>>> a.default_factory
<type 'list'>
That's what you see when you print abefore the data side of the dictionary appears.
这就是您print a在字典的数据侧出现之前所看到的。
So another trick to get more dictlike behaviour back without actually making a new object is to reset default_factory:
因此，在不实际创建新对象的情况下获得更多类似 dict 行为的另一个技巧是重置default_factory：
>>> a.default_factory = None
>>> a[4].append(10)
Traceback (most recent call last):
File "<ipython-input-6-0721ca19bee1>", line 1, in <module>
a[4].append(10)
KeyError: 4
but most of the time this isn't worth the trouble.
但大多数时候这不值得麻烦。
回答by white_gecko
If you even want a recursive version for converting a recursive defaultdictto a dictyou can try the following:
如果你连想一个递归版本的递归转换defaultdict到一个dict你可以尝试以下方法：
#! /usr/bin/env python3
from collections import defaultdict
def ddict():
return defaultdict(ddict)
def ddict2dict(d):
for k, v in d.items():
if isinstance(v, dict):
d[k] = ddict2dict(v)
return dict(d)
myddict = ddict()
myddict["a"]["b"]["c"] = "value"
print(myddict)
mydict = ddict2dict(myddict)
print(mydict)
回答by Meow
If your defaultdict is recursively defined, for example:
如果您的 defaultdict 是递归定义的，例如：
from collections import defaultdict
recurddict = lambda: defaultdict(recurddict)
data = recurddict()
data["hello"] = "world"
data["good"]["day"] = True
yet another simple way to convert defaultdict back to dict is to use jsonmodule
将 defaultdict 转换回 dict 的另一种简单方法是使用jsonmodule
import json
data = json.loads(json.dumps(data))
and of course, the values contented in your defaultdict need to be confined to json supported data types, but it shouldn't be a problem if you don't intent to store classes or functions in the dict.
当然，您的 defaultdict 中包含的值需要限于 json 支持的数据类型，但如果您不打算在 dict 中存储类或函数，这应该不是问题。
