Type Hints

December 11, 2020

Syntax support for type hints (Python 3.5+)

The Python runtime does not enforce function and variable type annotations. They can be used by third party tools such as type checkers, IDEs, linters, etc.

— https://docs.python.org/3/library/typing.html

Function Signature Annotations

from typing import Any, Dict, List, Tuple

def example(
        s: str,
        i: int,
        l: List[int],
        t: Tuple[int,int],
        tt: Tuple[Any,...]
    ) -> List[Tuple[Dict[str, int], bool]]:
  return

Variable Annotations

some_number: int           # variable without initial value
some_list: List[int] = []  # variable with initial value
t: Tuple[int, ...] = (1, 2, 3)
other_var: int  = 'a'      # Flagged as error by type