Anton Abrosimov <[email protected]> added the comment:
An alternative way:
from collections.abc import Mapping
from dataclasses import dataclass, fields, _FIELDS, _FIELD
class DataclassMappingMixin(Mapping):
def __iter__(self):
return (f.name for f in fields(self))
def __getitem__(self, key):
field = getattr(self, _FIELDS)[key]
if field._field_type is not _FIELD:
raise KeyError(f"'{key}' is not a dataclass field.")
return getattr(self, field.name)
def __len__(self):
return len(fields(self))
@dataclass
class MyDataclass(DataclassMappingMixin):
a: int = 1
b: int = 2
my_dataclass = MyDataclass(a='3')
print(my_dataclass.__class__.__mro__)
print(my_dataclass.__class__.__name__)
print(my_dataclass['a'])
print(my_dataclass['b'])
print(dict(my_dataclass))
print(dict(**my_dataclass))
print(fields(my_dataclass))
Result:
(<class '__main__.MyDataclass'>,
<class '__main__.DataclassMappingMixin'>,
<class 'collections.abc.Mapping'>,
<class 'collections.abc.Collection'>,
<class 'collections.abc.Sized'>,
<class 'collections.abc.Iterable'>,
<class 'collections.abc.Container'>,
<class 'object'>)
MyDataclass
3
2
{'a': '3', 'b': 2}
{'a': '3', 'b': 2}
(Field(name='a',type=<class 'int'>, ...),
Field(name='b',type=<class 'int'>, ...))
----------
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Python tracker <[email protected]>
<https://bugs.python.org/issue42742>
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