How to get class variables and type hints?

Question

Assume I define a class with class level variables with type hints (e.g. something like the new python 3.7 dataclasses)

class Person:
    name: str
    age: int

    def parse_me(self):
        "what do I do here??"

How can I get the pairs of (variable name, variable type)?

Possible duplicate of [How can I get Python 3.7 new dataclass field types?](https://stackoverflow.com/questions/51946571/how-can-i-get-python-3-7-new-dataclass-field-types) — Maor Refaeli, Oct 16 '18 at 15:00
Not a duplicate IMO. The other question is about the dataclasses for which there are different methods to extract annotations. — krassowski, Sep 11 '19 at 21:13

score 47 · Accepted Answer · edited Jan 08 '20 at 03:37

47

typing.get_type_hints is another method that doesn't involve accessing magic properties directly:

from typing import get_type_hints

class Person:
    name: str
    age: int

get_type_hints(Person)
# returns {'name': <class 'str'>, 'age': <class 'int'>}

edited Jan 08 '20 at 03:37

Gringo Suave

29,931
6
88
75

answered Sep 01 '19 at 21:43

Brendan

1,905
2
19
25

2

It also renders "forward" annotations given as strings. – Gringo Suave Jan 08 '20 at 03:36

score 24 · Answer 2 · answered Oct 16 '18 at 14:55

These type hints are based on Python annotations. They are available as the __annotations__ property. This goes for classes, as well as functions.

>>> class Person:
...     name: str
...     age: int
... 
>>> Person.__annotations__
{'name': <class 'str'>, 'age': <class 'int'>}
>>> def do(something: str) -> int:
...     ...
... 
>>> do.__annotations__
{'something': <class 'str'>, 'return': <class 'int'>}

How to get class variables and type hints?

2 Answers2

Linked

Related