如何在python中键入提示nametuple？

Question

Type hint can define the return type in python, so when a function return namedtuple type, then how to define it

def bar(func):
    def decorator(*args, **kwargs):
        return namedtuple('data', 'name user')(**func(*args, **kwargs))

    return update_wrapper(decorator, func)


@bar
def info() -> NamedTuple:
    return {'name': 'a1', 'user': 'b1'}

Expect type 'NamedTuple',got Dict[str,str] instead

As you know, the function info() return Dict[str, str] , but the decorator @bar change it. Now the function info() return a namedtuple object,so is there a way to indicate that the function info() return namedtupe object by type hint in python?

Answer 1

NamedTuple instances are created via collections.namedtuple() function.

Since you are interested in typing elements of namedtuple, you could create a custom type that inherits the typed version of NamedType (as mentioned by @jab) and use it in type hints as shown below.

from typing import NamedTuple

class CustomType(NamedTuple):
    name: str
    user: str

def info() -> CustomType:
    return CustomType('a1', 'b1')