shelve Namespace Reference

Data Structures
class	Shelf
class	BsdDbShelf
class	DbfilenameShelf

Functions
def	open

Variables
list	__all__ = ["Shelf","BsdDbShelf","DbfilenameShelf","open"]

Detailed Description

Manage shelves of pickled objects.

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 "pickle"
module can handle.  This includes most class instances, recursive data
types, and objects containing lots of shared sub-objects.  The keys
are ordinary strings.

To summarize the interface (key is a string, data is an arbitrary
object):

import shelve
d = shelve.open(filename) # open, with (g)dbm filename -- no suffix

d[key] = data   # store data at key (overwrites old data if
                # using an existing key)
data = d[key]   # retrieve data at key (raise KeyError if no
                # such key)
del d[key]      # delete data stored at key (raises KeyError
                # if no such key)
flag = d.has_key(key)   # true if the key exists
list = d.keys() # a list of all existing keys (slow!)

d.close()       # close it

Dependent on the implementation, closing a persistent dictionary may
or may not be necessary to flush changes to disk.

Function Documentation

def shelve.open	(		filename,
			flag = 'c'
	)

Open a persistent dictionary for reading and writing.

Argument is the filename for the dbm database.
See the module's __doc__ string for an overview of the interface.

Definition at line 151 of file shelve.py.

def open(filename, flag='c'):
    """Open a persistent dictionary for reading and writing.

    Argument is the filename for the dbm database.
    See the module's __doc__ string for an overview of the interface.
    """

    return DbfilenameShelf(filename, flag)

Variable Documentation

list __all__ = ["Shelf","BsdDbShelf","DbfilenameShelf","open"]

Definition at line 43 of file shelve.py.