AttributeError:“TraitCompound”对象没有属性“clone”

Question

假设我想使用Traits包创建一个“base”属性，可以是“无”字符串或字典，其中键为“hrf”或“fourier”或“fourier_-han”或“gamma”或“fir”，值为字典，键为“derivs”或“length”或“order”，值为列表或浮点）。例：

基数==“无”
或
bases=={'hrf'：{'derivs'：[0,0]}}
或
基=={'fourier'：{'length'：1.4，'顺序'：3}

如果我定义一个“无”字符串或一个字典，其中键为“hrf”或“fourier”或“fourier_-han”或“gamma”或“fir”，值为字典，键为“derivs”或“length”或“order”，值为列表），则工作正常：

>>> import traits.api as traits
>>> class Foo(traits.HasTraits):
...  bases = traits.Either(traits.Dict(traits.Enum("hrf","fourier","fourier_han","gamma","fir"),traits.Dict(traits.Enum("derivs","length","order"), traits.List)),'none',default={"hrf":{"derivs":[0,0]}})
... 
>>> foo=Foo()
>>> foo.bases
{'hrf': {'derivs': [0, 0]}}

但这并不是我想要的。如果现在我尝试在内部字典中使用list或float，则它不起作用：

 >>> import traits.api as traits
 >>> class Foo(traits.HasTraits):
...  bases = traits.Either(traits.Dict(traits.Enum("hrf","fourier","fourier_han","gamma","fir"),traits.Dict(traits.Enum("derivs","length","order"), traits.Either(traits.List, traits.Float))),'none',default={"hrf":{"derivs":[0,0]}})
... 
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "<stdin>", line 2, in Foo
  File "/home/econdami/.local/lib/python3.7/site-packages/traits/trait_types.py", line 2804, in __init__
    handler = handler.clone()
AttributeError: 'TraitCompound' object has no attribute 'clone'

为什么?

Answer 1

这不是我第一次与开发Traits项目的团队互动

As always, they very quickly managed to solve the problem and gave a very detailed answer on it.

简而言之，早在Traits 6.1中，一方面，我们更喜欢：

traits.Union(traits.Float, traits.List)

到

traits.Either(traits.Float, traits.List)

另一方面，请注意Union（）的default_value参数（default表示任一个（）。最好用其他方法初始化它