定义types.Dict和dict之间的区别? [英] Difference between defining typing.Dict and dict?
问题描述
typing.Dict
: 导入键入
def change_bandwidths(new_bandwidths:typing.Dict,
user_id:int,
user_name:str) - > bool:
print(new_bandwidths,user_id,user_name)
return False
def my_change_bandwidths(new_bandwidths:dict,
user_id:int,
user_name:str) - > bool:
print(new_bandwidths,user_id,user_name)
return True
def main():
my_id ,my_name = 23,Tiras
simple_dict = {Hello:Moon}
change_bandwidths(simple_dict,my_id,my_name)
new_dict = {new:energy source
my_change_bandwidths(new_dict,my_id,my_name)
如果__name__ ==__main__:
main()
他们都工作得很好,似乎没有什么区别。
我已阅读 打字
模块文档。
typing.Dict
或 dict
我应该在程序中使用哪一个?
没有什么不同之间使用一个简单的 typing.Dict
和 dict
,no。
但是, typing.Dict
是一个 通用类型 ,可让您指定密钥和值的类型 ,使其更灵活:
def change_bandwidths(new_bandwidths:typing.Dict [str,str],
user_id:int,
user_name:str) - > bool:
因此,很可能是在您的项目生命周期的某个时候你想定义字典参数更精确一点,在这一点上将 typing.Dict
扩展到 typing.Dict [key_type,value_type]
是替换 dict
的更小的变化。
您可以使用 映射
或< a href =https://docs.python.org/3/library/typing.html#typing.MutableMapping =nofollow> MutableMapping
这里的类型由于您的功能不需要更改映射,所以我会坚持使用映射
。一个 dict
是一个映射,但是您可以创建也满足映射界面的其他对象,并且您的功能可能仍然可以使用:
def change_bandwidths(new_bandwidths:typing.Mapping [str,str],
user_id:int,
user_name:str) - > bool:
现在您明确地告诉其他用户此功能,您的代码实际上不会>
您的实际执行只是期待一个对象打印。这可能是一个测试实现,但是如果您使用 new_bandwidths:typing.Any
,则代码将继续工作,因为Python中的任何对象都是可打印的。
I am practicing using type hints in Python 3.5. One of my colleague uses typing.Dict
:
import typing
def change_bandwidths(new_bandwidths: typing.Dict,
user_id: int,
user_name: str) -> bool:
print(new_bandwidths, user_id, user_name)
return False
def my_change_bandwidths(new_bandwidths: dict,
user_id: int,
user_name: str) ->bool:
print(new_bandwidths, user_id, user_name)
return True
def main():
my_id, my_name = 23, "Tiras"
simple_dict = {"Hello": "Moon"}
change_bandwidths(simple_dict, my_id, my_name)
new_dict = {"new": "energy source"}
my_change_bandwidths(new_dict, my_id, my_name)
if __name__ == "__main__":
main()
Both of them work just fine, there doesn't appear to be a difference.
I have read the typing
module documentation.
Between typing.Dict
or dict
which one should I use in the program?
There is no real difference between using a plain typing.Dict
and dict
, no.
However, typing.Dict
is a Generic type that lets you specify the type of the keys and values too, making it more flexible:
def change_bandwidths(new_bandwidths: typing.Dict[str, str],
user_id: int,
user_name: str) -> bool:
As such, it could well be that at some point in your project lifetime you want to define the dictionary argument a little more precisely, at which point expanding typing.Dict
to typing.Dict[key_type, value_type]
is a 'smaller' change than replacing dict
.
You can make this even more generic by using Mapping
or MutableMapping
types here; since your function doesn't need to alter the mapping, I'd stick with Mapping
. A dict
is one mapping, but you could create other objects that also satisfy the mapping interface, and your function might well still work with those:
def change_bandwidths(new_bandwidths: typing.Mapping[str, str],
user_id: int,
user_name: str) -> bool:
Now you are clearly telling other users of this function that your code won't actually alter the new_bandwidths
mapping passed in.
Your actual implementation is merely expecting an object that is printable. That may be a test implementation, but as it stands your code would continue to work if you used new_bandwidths: typing.Any
, because any object in Python is printable.
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