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Clean up pickle usage examples.

This commit is contained in:
Alexandre Vassalotti 2009-01-23 05:28:16 +00:00
parent f7d08c7d54
commit bcd1e3a453
1 changed files with 18 additions and 31 deletions
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49
Doc/library/pickle.rst
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@ -560,10 +560,8 @@ referenced object.
Here is a comprehensive example presenting how persistent ID can be used to Here is a comprehensive example presenting how persistent ID can be used to
pickle external objects by reference. pickle external objects by reference.
.. XXX Work around for some bug in sphinx/pygments.
.. highlightlang:: python
.. literalinclude:: ../includes/dbpickle.py .. literalinclude:: ../includes/dbpickle.py
.. highlightlang:: python3
.. _pickle-state: .. _pickle-state:
@ -715,46 +713,35 @@ solutions.
.. _pickle-example: .. _pickle-example:
Example Usage Examples
------- --------------
For the simplest code, use the :func:`dump` and :func:`load` functions. Note For the simplest code, use the :func:`dump` and :func:`load` functions. Note
that a self-referencing list is pickled and restored correctly. :: that a self-referencing list is pickled and restored correctly. ::
import pickle import pickle
data1 = {'a': [1, 2.0, 3, 4+6j], # An arbitrary collection of objects supported by pickle.
'b': ("string", "string using Unicode features \u0394"), data = {
'c': None} 'a': [1, 2.0, 3, 4+6j],
'b': ("character string", b"byte string"),
'c': set([None, True, False])
}
selfref_list = [1, 2, 3] with open('data.pickle', 'wb') as f:
selfref_list.append(selfref_list) # Pickle the 'data' dictionary using the highest protocol available.
pickle.dump(data, f, pickle.HIGHEST_PROTOCOL)
output = open('data.pkl', 'wb')
# Pickle dictionary using protocol 2. The following example reads the resulting pickled data. ::
pickle.dump(data1, output, 2)
# Pickle the list using the highest protocol available. import pickle
pickle.dump(selfref_list, output, -1)
output.close() with open('data.pickle', 'rb') as f:
# The protocol version used is detected automatically, so we do not
# have to specify it.
data = pickle.load(f)
The following example reads the resulting pickled data. When reading a
pickle-containing file, you should open the file in binary mode because you
can't be sure if the ASCII or binary format was used. ::
import pprint, pickle
pkl_file = open('data.pkl', 'rb')
data1 = pickle.load(pkl_file)
pprint.pprint(data1)
data2 = pickle.load(pkl_file)
pprint.pprint(data2)
pkl_file.close()
.. seealso:: .. seealso::