• Unpack

  • List of Tuples

  • username, password = ('Alice', 'Apricot')

  • for firstname,lastname in users

Problem:

>>> name = ('Alice', 'Apricot')
>>> firstname = name[0]
>>> lastname = name[1]

Solution:

>>> username, password = ('Alice', 'Apricot')

13.3.1. Problem

  • for user in DATA[1:]

>>> DATA = [
...     ('firstname', 'lastname', 'age'),
...     ('Alice', 'Apricot', 30),
...     ('Bob', 'Blackthorn', 31),
...     ('Carol', 'Corn', 32),
...     ('Dave', 'Durian', 33),
...     ('Eve', 'Elderberry', 34),
...     ('Mallory', 'Melon', 15),
... ]
>>>
>>> for user in DATA[1:]:
...     firstname = user[0]
...     lastname = user[1]
...     age = user[2]
...     print(f'{firstname=}, {lastname=}, {age=}')
...
firstname='Alice', lastname='Apricot', age=30
firstname='Bob', lastname='Blackthorn', age=31
firstname='Carol', lastname='Corn', age=32
firstname='Dave', lastname='Durian', age=33
firstname='Eve', lastname='Elderberry', age=34
firstname='Mallory', lastname='Melon', age=15

13.3.2. Solution

  • for firstname, lastname, age in DATA[1:]

>>> DATA = [
...     ('firstname', 'lastname', 'age'),
...     ('Alice', 'Apricot', 30),
...     ('Bob', 'Blackthorn', 31),
...     ('Carol', 'Corn', 32),
...     ('Dave', 'Durian', 33),
...     ('Eve', 'Elderberry', 34),
...     ('Mallory', 'Melon', 15),
... ]
>>>
>>> for firstname, lastname, age in DATA[1:]:
...     print(f'{firstname=}, {lastname=}, {age=}')
...
firstname='Alice', lastname='Apricot', age=30
firstname='Bob', lastname='Blackthorn', age=31
firstname='Carol', lastname='Corn', age=32
firstname='Dave', lastname='Durian', age=33
firstname='Eve', lastname='Elderberry', age=34
firstname='Mallory', lastname='Melon', age=15

13.3.3. Recap

  • Unpacking: a, b = 1, 2

  • Instead for row in data you can unpack for a,b in data

  • Unpack List of Tuples

13.3.4. Assignments

# %% About
# - Name: For Unpack Months
# - Difficulty: easy
# - Lines: 3
# - Minutes: 5

# %% 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

# %% English
# 1. Use `DATA: list[tuple]`
# 2. Define `result: dict` with month number and name:
#    - Keys: month number
#    - Values: month name
# 3. Use unpack syntax in a for loop
# 4. Run doctests - all must succeed

# %% Polish
# 1. Użyj `DATA: list[tuple]`
# 2. Zdefiniuj `result: dict` z numerem miesiąca i nazwą:
#    - Klucz: numer miesiąca
#    - Wartość: nazwa miesiąca
# 3. Użyj składni rozpakowania w pętli for
# 4. Uruchom doctesty - wszystkie muszą się powieść

# %% Expected
# >>> result
# {1: 'January',
#  2: 'February',
#  3: 'March',
#  4: 'April',
#  5: 'May',
#  6: 'June',
#  7: 'July',
#  8: 'August',
#  9: 'September',
#  10: 'October',
#  11: 'November',
#  12: 'December'}

# %% Hints
# - `a, b = (1, 2)`
# - `dict[key] = value`

# %% Doctests
"""
>>> import sys; sys.tracebacklimit = 0

>>> assert sys.version_info >= (3, 9), \
'Python has an is invalid version; expected: `3.9` or newer.'

>>> from pprint import pprint

>>> assert 'result' in globals(), \
'Variable `result` is not defined; assign result of your program to it.'

>>> assert result is not Ellipsis, \
'Variable `result` has an invalid value; assign result of your program to it.'

>>> assert type(result) is dict, \
'Variable `result` has an invalid type; expected: `dict`.'

>>> assert all(type(x) is int for x in result.keys())
>>> assert all(type(x) is str for x in result.values())
>>> assert all(x in result.keys() for x in range(1, 13))
>>> assert all(v in result.values() for k,v in DATA)

>>> 13 not in result
True
>>> 0 not in result
True

>>> pprint(result)
{1: 'January',
 2: 'February',
 3: 'March',
 4: 'April',
 5: 'May',
 6: 'June',
 7: 'July',
 8: 'August',
 9: 'September',
 10: 'October',
 11: 'November',
 12: 'December'}
"""

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

# %% Imports

# %% Types
result: dict[int,str]

# %% Data
DATA = [
    (1, 'January'),
    (2, 'February'),
    (3, 'March'),
    (4, 'April'),
    (5, 'May'),
    (6, 'June'),
    (7, 'July'),
    (8, 'August'),
    (9, 'September'),
    (10, 'October'),
    (11, 'November'),
    (12, 'December'),
]

# %% Result
result = ...


# %% About
# - Name: For Unpack Between
# - Difficulty: easy
# - Lines: 4
# - Minutes: 5

# %% 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

# %% English
# 1. Use `DATA: list[tuple]` variable
# 2. Define `result: list[tuple]` with first names and last names
#    of people whose age is greater or equal to 18
# 3. Use unpack syntax in a `for` loop
# 4. Run doctests - all must succeed

# %% Polish
# 1. Użyj zmiennej `DATA: list[tuple]`
# 2. Zdefiniuj `result: list[tuple]` z imionami i nazwiskami osób,
#    których wiek większy lub równy 18
# 3. Użyj składni rozpakowania w pętli `for`
# 4. Uruchom doctesty - wszystkie muszą się powieść

# %% Expected
# >>> result
# [('Alice', 'Apricot'),
#  ('Bob', 'Blackthorn'),
#  ('Carol', 'Corn'),
#  ('Dave', 'Durian'),
#  ('Eve', 'Elderberry')]

# %% Hints
# - `x >= 18`
# - `a, b, c = (1, 2, 3)`
# - `list.append()`

# %% Why
# - Check if you can filter data
# - Check if you know string methods
# - Check if you know how to iterate over `list[dict]`

# %% Doctests
"""
>>> import sys; sys.tracebacklimit = 0

>>> assert sys.version_info >= (3, 9), \
'Python has an is invalid version; expected: `3.9` or newer.'

>>> from pprint import pprint

>>> assert 'result' in globals(), \
'Variable `result` is not defined; assign result of your program to it.'

>>> assert result is not Ellipsis, \
'Variable `result` has an invalid value; assign result of your program to it.'

>>> assert type(result) is list, \
'Variable `result` has an invalid type; expected: `list`.'

>>> assert len(result) > 0, \
'Variable `result` has an invalid length; expected more than zero elements.'

>>> assert all(type(x) is tuple for x in result), \
'Variable `result` has elements of an invalid type; all items should be: `tuple`.'

>>> pprint(result, width=30)
[('Alice', 'Apricot'),
 ('Bob', 'Blackthorn'),
 ('Carol', 'Corn'),
 ('Dave', 'Durian'),
 ('Eve', 'Elderberry')]
"""

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

# %% Imports

# %% Types
result: list[tuple[str,str]]

# %% Data
DATA = [
    ('firstname', 'lastname', 'age'),
    ('Alice', 'Apricot', 30),
    ('Bob', 'Blackthorn', 31),
    ('Carol', 'Corn', 32),
    ('Dave', 'Durian', 33),
    ('Eve', 'Elderberry', 34),
    ('Mallory', 'Melon', 15),
]

header = DATA[0]
data = DATA[1:]

# %% Result
result = ...


# %% About
# - Name: For Unpack Endswith
# - Difficulty: easy
# - Lines: 4
# - Minutes: 5

# %% 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

# %% English
# 1. Use `DATA: list[tuple]`
# 2. Define `result: list` with:
#    email addresses from `DATA` with domain names listed in `DOMAINS`
# 3. Use unpack syntax in a for loop
# 4. Run doctests - all must succeed

# %% Polish
# 1. Użyj `DATA: list[tuple]`
# 2. Zdefiniuj `result: list` z:
#    adresami email z `DATA` z domenami wymienionymi w `DOMAINS`
# 3. Użyj składni rozpakowania w pętli for
# 4. Uruchom doctesty - wszystkie muszą się powieść

# %% Expected
# >>> result
# ['alice@example.com',
#  'bob@example.com',
#  'carol@example.com',
#  'dave@example.org',
#  'eve@example.org']

# %% Hints
# - `a, b, c = (1, 2, 3)`
# - `str.split()`
# - `x in list`
# - `list.append`

# %% Why
# - Check if you can filter data
# - Check if you know string methods
# - Check if you know how to iterate over `list[dict]`

# %% Doctests
"""
>>> import sys; sys.tracebacklimit = 0

>>> assert sys.version_info >= (3, 9), \
'Python has an is invalid version; expected: `3.9` or newer.'

>>> from pprint import pprint

>>> assert 'result' in globals(), \
'Variable `result` is not defined; assign result of your program to it.'

>>> assert result is not Ellipsis, \
'Variable `result` has an invalid value; assign result of your program to it.'

>>> assert type(result) is list, \
'Variable `result` has an invalid type; expected: `list`.'

>>> assert len(result) > 0, \
'Variable `result` has an invalid length; expected more than zero elements.'

>>> assert all(type(x) is str for x in result), \
'Variable `result` has elements of an invalid type; all items should be: `str`.'

>>> result = sorted(result)
>>> pprint(result)
['alice@example.com',
 'bob@example.com',
 'carol@example.com',
 'dave@example.org',
 'eve@example.org']
"""

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

# %% Imports

# %% Types
result: list[str]

# %% Data
DATA = [
    ('firstname', 'lastname', 'email'),
    ('Alice', 'Apricot', 'alice@example.com'),
    ('Bob', 'Blackthorn', 'bob@example.com'),
    ('Carol', 'Corn', 'carol@example.com'),
    ('Dave', 'Durian', 'dave@example.org'),
    ('Eve', 'Elderberry', 'eve@example.org'),
    ('Mallory', 'Melon', 'mallory@example.net'),
]

DOMAINS = ('example.com', 'example.org')

header = DATA[0]
data = DATA[1:]

# %% Result
result = ...


# %% About
# - Name: For Unpack Unique
# - Difficulty: easy
# - Lines: 3
# - Minutes: 5

# %% 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

# %% English
# 1. Use `DATA: list[tuple]`
# 2. Define `result: set` with unique group names from `DATA`
# 3. Skip if user has no group (i.e. group is `None`)
# 4. Use unpack syntax in a for loop
# 5. Run doctests - all must succeed

# %% Polish
# 1. Użyj `DATA: list[tuple]`
# 2. Zdefiniuj `result: set` z unikalnymi nazwami grup z `DATA`
# 3. Pomiń, jeśli użytkownik nie ma grupy (tzn. grupa jest `None`)
# 4. Użyj składni rozpakowania w pętli for
# 5. Uruchom doctesty - wszystkie muszą się powieść

# %% Expected
# >>> result
# {'users', 'staff', 'admins'}

# %% Hints
# - `a,b,c,d,e = (1,2,3,4,5)`
# - `set.add()`

# %% Doctests
"""
>>> import sys; sys.tracebacklimit = 0

>>> assert sys.version_info >= (3, 9), \
'Python has an is invalid version; expected: `3.9` or newer.'

>>> assert 'result' in globals(), \
'Variable `result` is not defined; assign result of your program to it.'

>>> assert result is not Ellipsis, \
'Variable `result` has an invalid value; assign result of your program to it.'

>>> assert type(result) is set, \
'Variable `result` has an invalid type; expected: `set`.'

>>> assert len(result) > 0, \
'Variable `result` has an invalid length; expected more than zero elements.'

>>> assert None not in result, \
'None cannot be in `result` - it is not a group name'

>>> assert all(type(x) is str for x in result), \
'Variable `result` has elements of an invalid type; all items should be: `str`.'

>>> assert len(result) == 3, \
'Variable `result` has an invalid length; expected: `3`.'

>>> 'users' in result
True
>>> 'staff' in result
True
>>> 'admins' in result
True
"""

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

# %% Imports

# %% Types
result: set[str]

# %% Data
DATA = [
    ('firstname', 'lastname', 'group'),
    ('Alice', 'Apricot', 'users'),
    ('Bob', 'Blackthorn', 'users'),
    ('Carol', 'Corn', 'staff'),
    ('Dave', 'Durian', 'staff'),
    ('Eve', 'Elderberry', 'admins'),
    ('Mallory', 'Melon', None),
]

# %% Result
result = ...