如何在python3中向自定义静态类型提示传递参数?

编译我的代码示例

必须从头开始设计类以接受静态类型提示。这不符合我最初的用例,因为我试图声明第三方类的特殊子类型,但它编译了我的代码示例。

from typing import Generic, TypeVar, Sequence, List

# Declare your own accepted types for your container, required
T = TypeVar('T', int, str, float)

# The custom container has be designed to accept types hints
class MyContainer(Sequence[T]):
    # some class definition ...

# Now, you can make a special container type
# Note that Sequence is a generic of List, and T is a generic of str, as defined above
SpecialContainer = TypeVar('SpecialContainer', MyContainer[List[str]])

# And this compiles
def f(data: SpecialContainer):
    # do something

子类型化第三方类

f() ,拍了一张照片 pd.DataFrame 对象,该对象由整数索引,其单元格均为字符串。利用上面的答案,我想出了一个巧妙的表达方式。

from typing import Mapping, TypeVar, NewType, NamedTuple
from pandas import pd

# Create custom types, required even if redundant
Index = TypeVar('Index')
Row = TypeVar('Row')

# Create a child class of pd.DataFrame that includes a type signature
# Note that Mapping is a generic for a key-value store
class pdDataFrame(pd.DataFrame, Mapping[Index, Row]):
    pass

# Now, this compiles, and explains what my special pd.DataFrame does
pdStringDataFrame = NewType('pdDataFrame', pdDataFrame[int, NamedTuple[str]])

# And this compiles
def f(data: pdStringDataFrame):
    pass

• 如果您正在编写一个类似于容器泛型的自定义类,比如 Sequence , Mapping Any

• 如果您试图对未实现类型提示的第三方类的特定用法进行注释:

  • 尝试使用现有的类型变量来理解你的观点,例如。 MyOrderedDictType = NewType('MyOrderedDictType', Dict[str, float])
  • 如果这样做不起作用,您将不得不用琐碎的子类和类型变量来混乱您的命名空间,以获得要编译的类型提示。最好使用docstring或注释来解释您的情况。