CODEWITHSUNDEEP
pythonpython-typing
juhat
juhat

Reputation: 396

How to create customizable Python type

I would like to create custom Python type hint that would effectively be

MyType = Dict[str, <some_type>]

Then I would like to be able to spesify MyType like MyType[<some_type>], for example MyType[List[str]] which would mean Dict[str, List[str]].

I haven't been able to figure out how to do this.

I've tried MyType = Dict[str, Any] but I don't know how to make Any be a variable. Any suggestions?

Upvotes: 2

Views: 1435

Answers (2)

Nikolay Zakirov
Nikolay Zakirov

Reputation: 1584

Does Generics answer your question?

from typing import TypeVar, Dict, List
X = TypeVar('X')
MyType = Dict[str, X]

def test_f(d: MyType[List[str]]) -> bool:
    pass

Upvotes: 3

Anton Yang-W&#228;lder
Anton Yang-W&#228;lder

Reputation: 934

If you're using Python 3.9 or newer, you can use standard collections directly:

StrList = list[str]
MyType = dict[str, StrList]

If you're using Python 3.7 or 3.8, you can still use the new notation via

from __future__ import annotations

Note: __future__ import statements must be located at the very top of a module

Upvotes: -1

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