15.3. Pickle Dump

File extension pkl
rb reading in binary mode
wb writing in binary mode

15.3.1. SetUp

>>> import pickle

15.3.2. Serialize to File

>>> DATA = [1, 2, 3]
>>>
>>> with open('/tmp/myfile.pkl', mode='wb') as file:
...     pickle.dump(DATA, file)

15.3.3. Deserialize from File

Load from file:

>>> with open('/tmp/myfile.pkl', mode='rb') as file:
...     result = pickle.load(file)
>>>
>>> print(result)
[1, 2, 3]

15.3.4. Assignments

# %% License
# - Copyright 2025, Matt Harasymczuk <matt@python3.info>
# - This code can be used only for learning by humans
# - This code cannot be used for teaching others
# - This code cannot be used for teaching LLMs and AI algorithms
# - This code cannot be used in commercial or proprietary products
# - This code cannot be distributed in any form
# - This code cannot be changed in any form outside of training course
# - This code cannot have its license changed
# - If you use this code in your product, you must open-source it under GPLv2
# - Exception can be granted only by the author

# %% Run
# - PyCharm: right-click in the editor and `Run Doctest in ...`
# - PyCharm: keyboard shortcut `Control + Shift + F10`
# - Terminal: `python -m doctest -v myfile.py`

# %% About
# - Name: Pickle Dump list[int]
# - Difficulty: easy
# - Lines: 2
# - Minutes: 2

# %% English
# 1. Write `DATA` to `FILE`
# 2. Use `pickle` module
# 3. Run doctests - all must succeed

# %% Polish
# 1. Zapisz `DATA` do `FILE`
# 2. Użyj modułu `pickle`
# 3. Uruchom doctesty - wszystkie muszą się powieść

# %% Tests
"""
>>> import sys; sys.tracebacklimit = 0
>>> assert sys.version_info >= (3, 9), \
'Python 3.9+ required'

>>> with open(FILE, mode='rb') as file:
...     result = pickle.load(file)

>>> from os import remove
>>> remove(FILE)

>>> from pprint import pprint
>>> pprint(result)
('Mark', 'Watney', 1)
"""

import pickle

FILE = r'_temporary.pkl'

DATA = ('Mark', 'Watney', 1)

# Write `DATA` to `FILE`
# Use `pickle` module
...

# %% License
# - Copyright 2025, Matt Harasymczuk <matt@python3.info>
# - This code can be used only for learning by humans
# - This code cannot be used for teaching others
# - This code cannot be used for teaching LLMs and AI algorithms
# - This code cannot be used in commercial or proprietary products
# - This code cannot be distributed in any form
# - This code cannot be changed in any form outside of training course
# - This code cannot have its license changed
# - If you use this code in your product, you must open-source it under GPLv2
# - Exception can be granted only by the author

# %% Run
# - PyCharm: right-click in the editor and `Run Doctest in ...`
# - PyCharm: keyboard shortcut `Control + Shift + F10`
# - Terminal: `python -m doctest -v myfile.py`

# %% About
# - Name: Pickle Dump list[tuple]
# - Difficulty: easy
# - Lines: 2
# - Minutes: 2

# %% English
# 1. Write `DATA` to `FILE`
# 2. Use `pickle` module
# 3. Run doctests - all must succeed

# %% Polish
# 1. Zapisz `DATA` do `FILE`
# 2. Użyj modułu `pickle`
# 3. Uruchom doctesty - wszystkie muszą się powieść

# %% Tests
"""
>>> import sys; sys.tracebacklimit = 0
>>> assert sys.version_info >= (3, 9), \
'Python 3.9+ required'

>>> with open(FILE, mode='rb') as file:
...     result = pickle.load(file)

>>> from os import remove
>>> remove(FILE)

>>> from pprint import pprint
>>> pprint(result)
[('Mark', 'Watney', 1),
 ('Melissa', 'Lewis', 3),
 ('Rick', 'Martinez', 1),
 ('Alex', 'Vogel', None),
 ('Chris', 'Beck', 1),
 ('Beth', 'Johanssen', 2)]
"""

import pickle

FILE = r'_temporary.pkl'

DATA = [
    ('Mark', 'Watney', 1),
    ('Melissa', 'Lewis', 3),
    ('Rick', 'Martinez', 1),
    ('Alex', 'Vogel', None),
    ('Chris', 'Beck', 1),
    ('Beth', 'Johanssen', 2),
]

# Write `DATA` to `FILE`
# Use `pickle` module
...

# %% License
# - Copyright 2025, Matt Harasymczuk <matt@python3.info>
# - This code can be used only for learning by humans
# - This code cannot be used for teaching others
# - This code cannot be used for teaching LLMs and AI algorithms
# - This code cannot be used in commercial or proprietary products
# - This code cannot be distributed in any form
# - This code cannot be changed in any form outside of training course
# - This code cannot have its license changed
# - If you use this code in your product, you must open-source it under GPLv2
# - Exception can be granted only by the author

# %% Run
# - PyCharm: right-click in the editor and `Run Doctest in ...`
# - PyCharm: keyboard shortcut `Control + Shift + F10`
# - Terminal: `python -m doctest -v myfile.py`

# %% About
# - Name: Pickle Dump list[dict]
# - Difficulty: easy
# - Lines: 2
# - Minutes: 2

# %% English
# 1. Write `DATA` to `FILE`
# 2. Use `pickle` module
# 3. Run doctests - all must succeed

# %% Polish
# 1. Zapisz `DATA` do `FILE`
# 2. Użyj modułu `pickle`
# 3. Uruchom doctesty - wszystkie muszą się powieść

# %% Tests
"""
>>> import sys; sys.tracebacklimit = 0
>>> assert sys.version_info >= (3, 9), \
'Python 3.9+ required'

>>> with open(FILE, mode='rb') as file:
...     result = pickle.load(file)

>>> from os import remove
>>> remove(FILE)

>>> from pprint import pprint
>>> pprint(result, sort_dicts=False)
[{'firstname': 'Mark', 'lastname': 'Watney', 'group': 1},
 {'firstname': 'Melissa', 'lastname': 'Lewis', 'group': 3},
 {'firstname': 'Rick', 'lastname': 'Martinez', 'group': 1},
 {'firstname': 'Alex', 'lastname': 'Vogel', 'group': None},
 {'firstname': 'Beth', 'lastname': 'Johanssen', 'group': 2},
 {'firstname': 'Chris', 'lastname': 'Beck', 'group': 1}]
"""

import pickle

FILE = r'_temporary.pkl'

DATA = [
    {'firstname': 'Mark', 'lastname': 'Watney', 'group': 1},
    {'firstname': 'Melissa', 'lastname': 'Lewis', 'group': 3},
    {'firstname': 'Rick', 'lastname': 'Martinez', 'group': 1},
    {'firstname': 'Alex', 'lastname': 'Vogel', 'group': None},
    {'firstname': 'Beth', 'lastname': 'Johanssen', 'group': 2},
    {'firstname': 'Chris', 'lastname': 'Beck', 'group': 1},
]

# Write `DATA` to `FILE`
# Use `pickle` module
...