我已经浏览了Python文档提供的信息，但我还是有点困惑。有人可以发布一个示例代码，编写一个新文件，然后使用pickle将字典转储到其中吗?
当前回答
一般来说，除非字典中只有简单的对象，如字符串和整数，否则pickle字典将会失败。
Python 2.7.9 (default, Dec 11 2014, 01:21:43)
[GCC 4.2.1 Compatible Apple Clang 4.1 ((tags/Apple/clang-421.11.66))] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> from numpy import *
>>> type(globals())
<type 'dict'>
>>> import pickle
>>> pik = pickle.dumps(globals())
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/pickle.py", line 1374, in dumps
Pickler(file, protocol).dump(obj)
File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/pickle.py", line 224, in dump
self.save(obj)
File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/pickle.py", line 286, in save
f(self, obj) # Call unbound method with explicit self
File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/pickle.py", line 649, in save_dict
self._batch_setitems(obj.iteritems())
File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/pickle.py", line 663, in _batch_setitems
save(v)
File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/pickle.py", line 306, in save
rv = reduce(self.proto)
File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/copy_reg.py", line 70, in _reduce_ex
raise TypeError, "can't pickle %s objects" % base.__name__
TypeError: can't pickle module objects
>>>
即使是一个非常简单的字典也经常会失败。这取决于内容。
>>> d = {'x': lambda x:x}
>>> pik = pickle.dumps(d)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/pickle.py", line 1374, in dumps
Pickler(file, protocol).dump(obj)
File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/pickle.py", line 224, in dump
self.save(obj)
File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/pickle.py", line 286, in save
f(self, obj) # Call unbound method with explicit self
File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/pickle.py", line 649, in save_dict
self._batch_setitems(obj.iteritems())
File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/pickle.py", line 663, in _batch_setitems
save(v)
File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/pickle.py", line 286, in save
f(self, obj) # Call unbound method with explicit self
File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/pickle.py", line 748, in save_global
(obj, module, name))
pickle.PicklingError: Can't pickle <function <lambda> at 0x102178668>: it's not found as __main__.<lambda>
然而，如果你使用一个更好的序列化器，如dill或cloudpickle，那么大多数字典都可以被pickle:
>>> import dill
>>> pik = dill.dumps(d)
或者如果你想保存你的字典到一个文件…
>>> with open('save.pik', 'w') as f:
... dill.dump(globals(), f)
...
后一个例子与这里发布的任何其他好的答案是一样的(除了忽略了字典内容的可选择性之外，这些答案都是好的)。
其他回答
试试这个:
import pickle
a = {'hello': 'world'}
with open('filename.pickle', 'wb') as handle:
pickle.dump(a, handle, protocol=pickle.HIGHEST_PROTOCOL)
with open('filename.pickle', 'rb') as handle:
b = pickle.load(handle)
print(a == b)
上面的解决方案没有任何特定于dict对象的内容。同样的方法也适用于许多Python对象，包括任意类的实例和任意复杂的数据结构嵌套。例如，将第二行替换为以下几行:
import datetime
today = datetime.datetime.now()
a = [{'hello': 'world'}, 1, 2.3333, 4, True, "x",
("y", [[["z"], "y"], "x"]), {'today', today}]
也会产生True的结果。
由于某些对象本身的性质，它们不能被pickle。例如，pickle包含打开文件句柄的结构是没有意义的。
>>> import pickle
>>> with open("/tmp/picklefile", "wb") as f:
... pickle.dump({}, f)
...
通常情况下，最好使用cPickle实现
>>> import cPickle as pickle
>>> help(pickle.dump)
Help on built-in function dump in module cPickle:
dump(...)
dump(obj, file, protocol=0) -- Write an object in pickle format to the given file.
See the Pickler docstring for the meaning of optional argument proto.
如果你只是想把字典存储在一个文件中，可以像这样使用pickle
import pickle
a = {'hello': 'world'}
with open('filename.pickle', 'wb') as handle:
pickle.dump(a, handle)
with open('filename.pickle', 'rb') as handle:
b = pickle.load(handle)
如果您想在多个文件中保存和恢复多个字典 缓存和存储更复杂的数据， 使用anycache。 泡菜周围的其他东西它都有
from anycache import anycache
@anycache(cachedir='path/to/files')
def myfunc(hello):
return {'hello', hello}
的参数来存储不同的myfunc结果 不同的文件在cachedir并重新加载它们。
有关更多详细信息，请参阅文档。
一般来说，除非字典中只有简单的对象，如字符串和整数，否则pickle字典将会失败。
Python 2.7.9 (default, Dec 11 2014, 01:21:43)
[GCC 4.2.1 Compatible Apple Clang 4.1 ((tags/Apple/clang-421.11.66))] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> from numpy import *
>>> type(globals())
<type 'dict'>
>>> import pickle
>>> pik = pickle.dumps(globals())
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/pickle.py", line 1374, in dumps
Pickler(file, protocol).dump(obj)
File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/pickle.py", line 224, in dump
self.save(obj)
File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/pickle.py", line 286, in save
f(self, obj) # Call unbound method with explicit self
File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/pickle.py", line 649, in save_dict
self._batch_setitems(obj.iteritems())
File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/pickle.py", line 663, in _batch_setitems
save(v)
File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/pickle.py", line 306, in save
rv = reduce(self.proto)
File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/copy_reg.py", line 70, in _reduce_ex
raise TypeError, "can't pickle %s objects" % base.__name__
TypeError: can't pickle module objects
>>>
即使是一个非常简单的字典也经常会失败。这取决于内容。
>>> d = {'x': lambda x:x}
>>> pik = pickle.dumps(d)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/pickle.py", line 1374, in dumps
Pickler(file, protocol).dump(obj)
File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/pickle.py", line 224, in dump
self.save(obj)
File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/pickle.py", line 286, in save
f(self, obj) # Call unbound method with explicit self
File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/pickle.py", line 649, in save_dict
self._batch_setitems(obj.iteritems())
File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/pickle.py", line 663, in _batch_setitems
save(v)
File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/pickle.py", line 286, in save
f(self, obj) # Call unbound method with explicit self
File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/pickle.py", line 748, in save_global
(obj, module, name))
pickle.PicklingError: Can't pickle <function <lambda> at 0x102178668>: it's not found as __main__.<lambda>
然而，如果你使用一个更好的序列化器，如dill或cloudpickle，那么大多数字典都可以被pickle:
>>> import dill
>>> pik = dill.dumps(d)
或者如果你想保存你的字典到一个文件…
>>> with open('save.pik', 'w') as f:
... dill.dump(globals(), f)
...
后一个例子与这里发布的任何其他好的答案是一样的(除了忽略了字典内容的可选择性之外，这些答案都是好的)。
将Python数据(例如字典)转储到pickle文件的简单方法。
import pickle
your_dictionary = {}
pickle.dump(your_dictionary, open('pickle_file_name.p', 'wb'))
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