遍历数据类并填充值

Question

我想用值填充数据类（不是在初始化时）。我试过了：

from random import randint
from dataclasses import dataclass

@dataclass
class VData:
    var_a: list = None
    var_b: list = None
    var_c: list = None

X = VData

for var in VData.__dataclass_fields__:
    l = [randint(0, 10), randint(0,10)]
    X.__setattr__(X, var, l)

但出现错误：can't apply this __setattr__ to type object。如何正确循环变量？

Answer 1

使用 asdict 和 setattr 而不是它们的等价物。

from random import randint
from dataclasses import dataclass, asdict

@dataclass
class VData:
    var_a: list = None
    var_b: list = None
    var_c: list = None
# you were missing a () which instantiates the object
inst = VData()

# Here, asdict gives you the dictionary form of a dataclass instance
# fields would work too as @rv.ketch pointed out
# if you don't have a need for the values of the dict
for var in asdict(inst):
    l = [randint(0, 10), randint(0,10)]
    setattr(inst, var, l)

print(inst)

Answer 2

使用fields。作为一般规则，避免像 __setattr__ 这样的魔术方法。

from random import randint
from dataclasses import dataclass, fields


@dataclass
class VData:
    var_a: list = None
    var_b: list = None
    var_c: list = None

X = VData()
xfilds = fields(VData)

for var in xfilds:
    l = [randint(0, 10), randint(0,10)]
    setattr(X, var.name, l)

# VData(var_a=[10, 2], var_b=[8, 9], var_c=[0, 6])

注意：xfilds被缓存，asdict没有。

遍历数据类并填充值

Looping over a dataclass and fill values

python-3.x

python-dataclasses