Enforce parameter casing for functions and classes python

Question

I want python to raise an exception if the argument type does not match the parameter type. Function example:

def add_integers (a: int, b:int) -> int:
    return a + b

What that function will return with different arguments

add_integers(1,2) = 3
add_integers(True,2) = 3
add_integers("1",2) = Exception (because it cannot add str and int)

I want to make sure that the function does not except an argument of type boolean and ONLY integers. I know I can make an if statement to check the type and raise an exception myself or maybe use a decorator function , but I was wondering if there is a simpler way of doing it?

It is not raised for booleans in this case, python will handle True as 1, but I want it to give me a TypeError — Joanthan Ahrenkiel-Frellsen
– Joanthan Ahrenkiel-Frellsen, Commented Jul 9, 2022 at 8:48
My opinion is that you will be better off having a unit test check these things. What advantage do you get with an exception at runtime? — quamrana
– quamrana, Commented Jul 9, 2022 at 8:52
If you want python to work more like a statically typed language, you should check out mypy. Without mypy type hints only serve as code documentation. — janq0
– janq0, Commented Jul 9, 2022 at 9:42

slimmsady · Accepted Answer · 2022-07-09 08:57:39Z

1

You can use the built-in function type . This returns the class of the object and does not consider sub-classes. Which is an issue with isinstance as it will also return true if you check if a boolean is an int

>>> type(1) is int
True
>>> type(True) is int
False

answered Jul 9, 2022 at 8:57

slimmsady

561 silver badge3 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

Enforce parameter casing for functions and classes python

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related