ruk·si

🐍 Python
shelve

Updated at 2018-06-11 01:07

shelve is a dictionary-like object that can be saved to disk in a binary format. Values can be anything that can be pickled.

import os
import shelve

DB_FILE = './what.shelve'

# .open() will create the file if it doesn't exist
with shelve.open(DB_FILE) as db:
    db['owner'] = 'Ruksi'
    db['people'] = []

    # by default, stuff is written ONLY on assignment
    # not when a mutable variable e.g. list is changed
    temp = db['people']
    temp.append({'name': 'John'})
    db['people'] = temp

with shelve.open(DB_FILE) as db:
    assert db['owner'] == 'Ruksi'
    assert db['people'] == [{'name': 'John'}]

with shelve.open(DB_FILE) as db:
    del db['owner']
    del db['people']

try:
    os.remove(DB_FILE)
except OSError:
    pass

Sources

  • Fluent Python, Luciano Ramalho