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
import pickle
dictobj = {'Jack' : 123, 'John' : 456}
filename = "/foldername/filestore"
fileobj = open(filename, 'wb')
pickle.dump(dictobj, fileobj)
fileobj.close()
其他回答
# Save a dictionary into a pickle file.
import pickle
favorite_color = {"lion": "yellow", "kitty": "red"} # create a dictionary
pickle.dump(favorite_color, open("save.p", "wb")) # save it into a file named save.p
# -------------------------------------------------------------
# Load the dictionary back from the pickle file.
import pickle
favorite_color = pickle.load(open("save.p", "rb"))
# favorite_color is now {"lion": "yellow", "kitty": "red"}
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'))
如果你想在不打开文件的情况下在一行中处理写入或读取:
import joblib
my_dict = {'hello': 'world'}
joblib.dump(my_dict, "my_dict.pickle") # write pickle file
my_dict_loaded = joblib.load("my_dict.pickle") # read pickle file
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)。
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。
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