import dbm

import pickle

db = dbm.open('captions', 'c')

# When you create a new item in the db, dbm updates the database file

db['cleese.png'] = 'Photo of John Cleese.' # Store string into the db

# When you access one of the items, dbm reads the db file:

print(db['cleese.png']) # Display the value in the db

## b'Photo of John Cleese.'

# The result is a bytes (string) object, which is why it begins with b.

#------------------------------------------------------------------------------

# If you make another assignment to an existing key, dbm replaces the old value:

db['cleese.png'] = 'Photo of John Cleese doing a silly walk.'

print(db['cleese.png'])

## 'Photo of John Cleese doing a silly walk.'

#------------------------------------------------------------------------------

# Example of using pickling on numbers to store their values into a db

t1 = [1, 2, 3]

s1 = pickle.dumps(t1) # Dump string (pickle) the numberic list into a byte string

print("\nList =", t1) # Display the original list

print("Pickle List original =\t", s1) # Display the byte string (pickled)

db['answers'] = s1 # Store the pickled byte string in the db

s2 = db['answers'] # Retrieve the byte string from the db

t2 = pickle.loads(s2) # Load the byte string (reconstitute) into a numberic list

print("\nPickle list from db =\t", s2) # Display the retrieved byte string from the db

print("List from db =", t2) # Display numeric list from the reconstituted byte string

db.close()