[英]How to pickle an class that inherits from collections.deque?
示例很清楚,我有一个继承到deque的类和一个模块'collections'的方法,有时我使用defaultdict,有些则不然。
>>> from collections import deque, defaultdict
>>> import pickle
>>> class lista(deque):
... def __init__(self):
... deque.__init__(self)
... self.lib = defaultdict(dict)
...
>>> p = lista()
>>> p.append("a")
>>> p.append("b")
>>> p.lib['t']=0
>>> p.__reduce__()
(<class '__main__.lista'>, (['a', 'b'], None), {'lib': defaultdict(<type 'dict'>, {'t': 0})})
>>> pik = pickle.dumps(p)
>>> unpik = pickle.loads(pik)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/pickle.py", line 1382, in loads
File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/pickle.py", line 858, in load
File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/pickle.py", line 1133, in load_reduce
TypeError: __init__() takes exactly 1 argument (3 given)
>>>
最后一个问题,如何序列化这个对象?
Deque 初始化最多3个args :
class collections.deque([iterable[, maxlen]])
在进行unpickling时,会提供所有三个(包括self),而__init__
则不接受它们。 例如更改为
class lista(deque):
def __init__(self, iterable=(), maxlen=None):
deque.__init__(self, iterable, maxlen)
self.lib = defaultdict(dict)
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