Python Shelve Module

From the Python 3 documentation

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.

Save variables

>>> import shelve >>> wife = ['Pretty', 'Lovely', 'Nice'] >>> with shelve.open('mydata') as shelf_file: ... shelf_file['wife'] = wife 

Open and read variables

>>> with shelve.open('mydata') as shelf_file: ... print(type(shelf_file)) ... print(shelf_file['wife']) ... # <class 'shelve.DbfilenameShelf'> # ['Pretty', 'Lovely', 'Nice'] 

Just like dictionaries, shelf values have keys() and values() methods that will return list-like values of the keys and values in the shelf. Since these methods return list-like values instead of true lists, you should pass them to the list() function to get them in list form.

>>> with shelve.open('mydata') as shelf_file: ... print(list(shelf_file.keys())) ... print(list(shelf_file.values())) ... # ['wife'] # [['Pretty', 'Lovely', 'Nice']] 

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