4.2. Dataclass Define Basic

4.2.1. SetUp

>>> from dataclasses import dataclass

4.2.2. Required Fields

>>> @dataclass
... class User:
...     firstname: str
...     lastname: str

4.2.3. Default Fields

>>> @dataclass
... class User:
...     firstname: str
...     lastname: str
...     role: str = 'admin'

4.2.4. Lists

>>> @dataclass
... class User:
...     firstname: str
...     lastname: str
...     groups: list[str]

4.2.5. Assignments

Code 4.39. Solution

"""
* Assignment: Dataclass DefineBasic Syntax
* Complexity: easy
* Lines of code: 4 lines
* Time: 3 min

English:
    1. Use Dataclass to define class `Point` with attributes:
        a. `x: int` with default value `0`
        b. `y: int` with default value `0`
    2. Run doctests - all must succeed

Polish:
    1. Użyj Dataclass do zdefiniowania klasy `Point` z atrybutami:
        a. `x: int` z domyślną wartością `0`
        b. `y: int` z domyślną wartością `0`
    2. Uruchom doctesty - wszystkie muszą się powieść

Tests:
    >>> import sys; sys.tracebacklimit = 0
    >>> from inspect import isclass
    >>> from dataclasses import is_dataclass

    >>> assert isclass(Point), 'Point is not a class'
    >>> assert is_dataclass(Point), 'Point is not a dataclass, add decorator'
    >>> assert hasattr(Point, 'x')
    >>> assert hasattr(Point, 'y')

    >>> Point()
    Point(x=0, y=0)

    >>> Point(x=0, y=0)
    Point(x=0, y=0)

    >>> Point(x=1, y=2)
    Point(x=1, y=2)
"""

from dataclasses import dataclass


# Use Dataclass to define class `Point` with attributes `x` and `y`
# type: type
class Point:
    ...

Code 4.40. Solution

"""
* Assignment: Dataclass DefineBasic Flat
* Complexity: easy
* Lines of code: 8 lines
* Time: 3 min

English:
    1. You received input data in JSON format from the API
    2. Using `dataclass` model data to create class `Pet`
    3. Run doctests - all must succeed

Polish:
    1. Otrzymałeś z API dane wejściowe w formacie JSON
    2. Wykorzystując `dataclass` zamodeluj dane aby stwórzyć klasę `Pet`
    3. Uruchom doctesty - wszystkie muszą się powieść

References:
    [1]: https://petstore.swagger.io/#/pet/getPetById

Tests:
    >>> import sys; sys.tracebacklimit = 0
    >>> from inspect import isclass
    >>> from dataclasses import is_dataclass
    >>> import json

    >>> assert isclass(Pet)
    >>> assert is_dataclass(Pet)

    >>> fields = {'id', 'category', 'name', 'photoUrls', 'tags', 'status'}
    >>> assert set(Pet.__dataclass_fields__.keys()) == fields, \
    f'Invalid fields, your fields should be: {fields}'

    >>> data = json.loads(DATA)
    >>> result = Pet(**data)

    >>> result  # doctest: +NORMALIZE_WHITESPACE
    Pet(id=0, category='dogs', name='doggie', photoUrls='img/dogs/0.png',
        tags=['dog', 'hot-dog'], status='available')
"""

from dataclasses import dataclass


DATA = """
{
  "id": 0,
  "category": "dogs",
  "name": "doggie",
  "photoUrls": "img/dogs/0.png",
  "tags": ["dog", "hot-dog"],
  "status": "available"
}
"""


# Using `dataclass` model data to create class `Pet`
# type: type
@dataclass
class Pet:
    ...

Code 4.41. Solution

"""
* Assignment: Dataclass DefineBasic Nested
* Complexity: easy
* Lines of code: 8 lines
* Time: 3 min

English:
    1. You received input data in JSON format from the API
    2. Using `dataclass` model `DATA` to create class `Pet`
       a. Leave `category` as `dict`
       b. Leave `tags` as `list[dicts]`
    3. Run doctests - all must succeed

Polish:
    1. Otrzymałeś z API dane wejściowe w formacie JSON
    2. Wykorzystując `dataclass` zamodeluj `DATA` aby stwórzyć klasę `Pet`
       a. Pozostaw `category` jako `dict`
       b. Pozostaw `tags` jako `list[dicts]`
    3. Uruchom doctesty - wszystkie muszą się powieść

References:
    [1]: https://petstore.swagger.io/#/pet/getPetById

Tests:
    >>> import sys; sys.tracebacklimit = 0
    >>> from inspect import isclass
    >>> from dataclasses import is_dataclass
    >>> import json

    >>> assert isclass(Pet)
    >>> assert is_dataclass(Pet)

    >>> fields = {'id', 'category', 'name', 'photoUrls', 'tags', 'status'}
    >>> assert set(Pet.__dataclass_fields__.keys()) == fields, \
    f'Invalid fields, your fields should be: {fields}'

    >>> data = json.loads(DATA)
    >>> result = Pet(**data)

    >>> result  # doctest: +NORMALIZE_WHITESPACE
    Pet(id=0, category={'id': 0, 'name': 'dogs'}, name='doggie',
        photoUrls=['img/dogs/0.png'], tags=[{'id': 0, 'name': 'dog'},
                                            {'id': 1, 'name': 'hot-dog'}],
        status='available')
"""

from dataclasses import dataclass


DATA = """
{
  "id": 0,
  "category": {
    "id": 0,
    "name": "dogs"
  },
  "name": "doggie",
  "photoUrls": [
    "img/dogs/0.png"
  ],
  "tags": [
    {
      "id": 0,
      "name": "dog"
    },
    {
      "id": 1,
      "name": "hot-dog"
    }
  ],
  "status": "available"
}
"""


# Using `dataclass` model data to create class `Pet`
# type: type
@dataclass
class Pet:
    ...