diff options
Diffstat (limited to 'Doc/library/shelve.rst')
| -rw-r--r-- | Doc/library/shelve.rst | 23 |
1 files changed, 17 insertions, 6 deletions
diff --git a/Doc/library/shelve.rst b/Doc/library/shelve.rst index b281814..9d7d504 100644 --- a/Doc/library/shelve.rst +++ b/Doc/library/shelve.rst @@ -7,6 +7,10 @@ .. index:: module: pickle +**Source code:** :source:`Lib/shelve.py` + +-------------- + A "shelf" is a persistent, dictionary-like object. The difference with "dbm" databases is that the values (not the keys!) in a shelf can be essentially arbitrary Python objects --- anything that the :mod:`pickle` module can handle. @@ -14,7 +18,7 @@ This includes most class instances, recursive data types, and objects containing lots of shared sub-objects. The keys are ordinary strings. -.. function:: open(filename[, flag='c'[, protocol=None[, writeback=False]]]) +.. function:: open(filename, flag='c', protocol=None, writeback=False) Open a persistent dictionary. The filename specified is the base filename for the underlying database. As a side-effect, an extension may be added to the @@ -97,7 +101,7 @@ Restrictions implementation used. -.. class:: Shelf(dict[, protocol=None[, writeback=False]]) +.. class:: Shelf(dict, protocol=None, writeback=False, keyencoding='utf-8') A subclass of :class:`collections.MutableMapping` which stores pickled values in the *dict* object. @@ -111,8 +115,15 @@ Restrictions This allows natural operations on mutable entries, but can consume much more memory and make sync and close take a long time. + The *keyencoding* parameter is the encoding used to encode keys before they + are used with the underlying dict. + + .. versionadded:: 3.2 + The *keyencoding* parameter; previously, keys were always encoded in + UTF-8. -.. class:: BsdDbShelf(dict[, protocol=None[, writeback=False]]) + +.. class:: BsdDbShelf(dict, protocol=None, writeback=False, keyencoding='utf-8') A subclass of :class:`Shelf` which exposes :meth:`first`, :meth:`!next`, :meth:`previous`, :meth:`last` and :meth:`set_location` which are available @@ -121,11 +132,11 @@ Restrictions modules. The *dict* object passed to the constructor must support those methods. This is generally accomplished by calling one of :func:`bsddb.hashopen`, :func:`bsddb.btopen` or :func:`bsddb.rnopen`. The - optional *protocol* and *writeback* parameters have the same interpretation - as for the :class:`Shelf` class. + optional *protocol*, *writeback*, and *keyencoding* parameters have the same + interpretation as for the :class:`Shelf` class. -.. class:: DbfilenameShelf(filename[, flag='c'[, protocol=None[, writeback=False]]]) +.. class:: DbfilenameShelf(filename, flag='c', protocol=None, writeback=False) A subclass of :class:`Shelf` which accepts a *filename* instead of a dict-like object. The underlying file will be opened using :func:`dbm.open`. By |