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-rw-r--r--Doc/library/pickle.rst49
1 files changed, 18 insertions, 31 deletions
diff --git a/Doc/library/pickle.rst b/Doc/library/pickle.rst
index a1e045d..4b329ae 100644
--- a/Doc/library/pickle.rst
+++ b/Doc/library/pickle.rst
@@ -560,10 +560,8 @@ referenced object.
Here is a comprehensive example presenting how persistent ID can be used to
pickle external objects by reference.
-.. XXX Work around for some bug in sphinx/pygments.
-.. highlightlang:: python
.. literalinclude:: ../includes/dbpickle.py
-.. highlightlang:: python3
+
.. _pickle-state:
@@ -715,46 +713,35 @@ solutions.
.. _pickle-example:
-Example
--------
+Usage Examples
+--------------
For the simplest code, use the :func:`dump` and :func:`load` functions. Note
that a self-referencing list is pickled and restored correctly. ::
import pickle
- data1 = {'a': [1, 2.0, 3, 4+6j],
- 'b': ("string", "string using Unicode features \u0394"),
- 'c': None}
-
- selfref_list = [1, 2, 3]
- selfref_list.append(selfref_list)
-
- output = open('data.pkl', 'wb')
-
- # Pickle dictionary using protocol 2.
- pickle.dump(data1, output, 2)
-
- # Pickle the list using the highest protocol available.
- pickle.dump(selfref_list, output, -1)
-
- output.close()
+ # An arbitrary collection of objects supported by pickle.
+ data = {
+ 'a': [1, 2.0, 3, 4+6j],
+ 'b': ("character string", b"byte string"),
+ 'c': set([None, True, False])
+ }
-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. ::
+ with open('data.pickle', 'wb') as f:
+ # Pickle the 'data' dictionary using the highest protocol available.
+ pickle.dump(data, f, pickle.HIGHEST_PROTOCOL)
- import pprint, pickle
- pkl_file = open('data.pkl', 'rb')
+The following example reads the resulting pickled data. ::
- data1 = pickle.load(pkl_file)
- pprint.pprint(data1)
+ import pickle
- data2 = pickle.load(pkl_file)
- pprint.pprint(data2)
+ 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)
- pkl_file.close()
.. seealso::