Modern Python Standard Library Cookbook

How to do it...

Perform the following steps for this recipe:

1. shelf, implemented by shelve, can be opened like any other file in Python. Once opened, it's possible to read and write keys into it like a dictionary:

>>> with shelve.open('/tmp/shelf.db') as shelf:
...   shelf['value'] = 5
... 

2. Values stored into shelf can be read back as a dictionary, too:

>>> with shelve.open('/tmp/shelf.db') as shelf:
...   print(shelf['value'])
... 
5

3. Complex values, or even custom classes, can be stored in shelve:

>>> class MyClass(object): ... def __init__(self, value): ... self.value = value ... >>> with shelve.open('/tmp/shelf.db') as shelf: ... shelf['value'] = MyClass(5) ... >>> with shelve.open('/tmp/shelf.db') as shelf: ... print(shelf['value']) ... ...