在 Python 中使用 None 值删除字典中键的正确方法
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Proper way to remove keys in dictionary with None values in Python
提问by Newboy11
What is the proper way to remove keys from a dictionary with value == Nonein Python?
从NonePython 中具有值 == 的字典中删除键的正确方法是什么？
回答by mgilson
Generally, you'll create a new dictconstructed from filtering the old one. dictionary comprehensions are great for this sort of thing:
通常，您将dict通过过滤旧构造来创建一个新构造。字典理解非常适合这类事情：
{k: v for k, v in original.items() if v is not None}
If you mustupdate the original dict, you can do it like this ...
如果您必须更新原始字典，您可以这样做...
filtered = {k: v for k, v in original.items() if v is not None}
original.clear()
original.update(filtered)
This is probably the most "clean" way to remove them in-place that I can think of (it isn't safe to modify a dict while you're iterating over it)
这可能是我能想到的就地删除它们的最“干净”的方式（在迭代时修改 dict 是不安全的）
Use original.iteritems()on python2.x
original.iteritems()在 python2.x 上使用
回答by Josh Weinstein
You can also do this using the del command
您也可以使用 del 命令执行此操作
f = {};
f['win']=None
f
=> {'win': None}
del f['win']
Or if you want this in a function format you could do:
或者，如果您希望以函数格式执行此操作，则可以执行以下操作：
def del_none_keys(dict):
for elem in dict.keys():
if dict[elem] == None:
del dict[elem]
回答by Paul Rooney
You could also take a copy of the dictto avoid iterating the original dictwhile altering it.
您还可以复制 ，dict以避免dict在更改原始文件时对其进行迭代。
for k, v in dict(d).items():
if v is None:
del d[k]
But that might not be a great idea for larger dictionaries.
但这对于较大的词典来说可能不是一个好主意。
回答by user2340939
For python 2.x:
对于python 2.x：
dict((k, v) for k, v in original.items() if v is not None)
