Python Forum
Should a function ever be more permissive than its type hints?
Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
Should a function ever be more permissive than its type hints?
#1
Here is some (trimmed) code, written by Guido for the random module.

    def randrange(start, stop=None, step=1):
        """Choose a random item from range(start, stop[, step]).
        """
        istart = int(start)
        if istart != start:
            raise ValueError("non-integer arg 1 for randrange()")
        # [don't reference start again, use istart from here]
Here, Guido allows not only an int argument for start, but any argument that can be cast into an int. So 1 will work for start, and so will 2.0 or even "3".

Of course, neither 2.1 nor "3.1" will work. Not even "3.0" will work.

I'd like to know how you would type hint such a function.

# describe intention?
def randrange(start: int, ... 

# or describe functionality?
def randrange(start: Union[int, float, str], ...
Reply


Messages In This Thread
Should a function ever be more permissive than its type hints? - by Shay - Mar-13-2019, 04:28 PM

Possibly Related Threads…
Thread Author Replies Views Last Post
  determine parameter type in definition function akbarza 1 591 Aug-24-2023, 01:46 PM
Last Post: deanhystad
  i want to use type= as a function/method keyword argument Skaperen 9 1,863 Nov-06-2022, 04:28 AM
Last Post: Skaperen
  match type with value in csv parsing function vinci 2 1,316 Jan-21-2022, 12:19 PM
Last Post: Larz60+
  SQLAlchemy with type hints gontajones 1 6,763 Jun-17-2020, 06:52 PM
Last Post: gontajones
  Creating function inside classes using type wolfmansbrother 3 2,343 Mar-20-2020, 01:21 AM
Last Post: wolfmansbrother
  Type hints and style MaxPowers 1 1,864 Feb-19-2020, 06:56 PM
Last Post: micseydel
  Type hinting - return type based on parameter micseydel 2 2,492 Jan-14-2020, 01:20 AM
Last Post: micseydel
  Getting type from input() function in Python 3.0 leodavinci1990 7 3,752 Jul-29-2019, 08:28 PM
Last Post: avorane
  Type function does not work sunnyarora 2 2,493 Mar-15-2019, 10:50 AM
Last Post: sunnyarora
  Parameters type in a function girbinho 2 2,747 Oct-09-2018, 10:36 PM
Last Post: micseydel

Forum Jump:

User Panel Messages

Announcements
Announcement #1 8/1/2020
Announcement #2 8/2/2020
Announcement #3 8/6/2020