Rick van Hattem
60 lines
1.2 KiB
ReStructuredText
60 lines
1.2 KiB
ReStructuredText
>>> spam: int
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>>> __annotations__['spam']
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<class 'int'>
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>>> spam = 'not a number'
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>>> __annotations__['spam']
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<class 'int'>
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>>> import dataclasses
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>>> @dataclasses.dataclass
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... class Sandwich:
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... spam: int
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... eggs: int = 3
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>>> Sandwich(1, 2)
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Sandwich(spam=1, eggs=2)
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>>> sandwich = Sandwich(4)
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>>> sandwich
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Sandwich(spam=4, eggs=3)
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>>> sandwich.eggs
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3
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>>> dataclasses.asdict(sandwich)
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{'spam': 4, 'eggs': 3}
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>>> dataclasses.astuple(sandwich)
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(4, 3)
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>>> help(dataclasses.dataclass)
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Help on ... dataclass(..., *, init=True, repr=True, eq=True, ...
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>>> def __init__(self, spam, eggs=3):
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... self.spam = spam
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... self.eggs = eggs
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>>> import typing
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>>> @dataclasses.dataclass
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... class Group:
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... name: str
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... parent: 'Group' = None
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>>> @dataclasses.dataclass
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... class User:
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... username: str
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... email: str = None
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... groups: typing.List[Group] = None
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>>> users = Group('users')
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>>> admins = Group('admins', users)
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>>> rick = User('rick', groups=[admins])
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>>> gvr = User('gvanrossum', 'guido@python.org', [admins])
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>>> rick.groups
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[Group(name='admins', parent=Group(name='users', parent=None))]
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>>> rick.groups[0].parent
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Group(name='users', parent=None)
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