How can I declare the type of variable if it is a class I created? (Python)

Asked Feb 04 '20 at 01:36

Active Feb 04 '20 at 01:38

Viewed 37 times

So I have some code as follows

 class Circle: 
    def __init__(self, x0, y0, r): 
        self.x0 = x0 
        self.y0 = y0
        self.r= r
    ##Method checking whether a given point is in the circle
    def is_in(self, pos):
        if (self.x0 - pos[0])**2 + (self.y0 - pos[1])**2 <= self.r: 
            return True 
        return False 

    ##method checking whether two circles intersect
    def intersect(self, circle2): 
        dist_sqrd = (self.x0 - circle2.x0)**2 + (self.y0 - circle2.y0)**2

        if np.sqrt(dist_sqrd) <= self.r + circle2.r: 
            return True 
        return False

Now in the second function intersect I want to specify that the second arugment must be another circle, i.e. same type as self. How can I do this?

edited Feb 04 '20 at 01:38

asked Feb 04 '20 at 01:36

Enforce

That dupe mentions return type, but it's the same for parameters. – Carcigenicate Feb 04 '20 at 01:38
I'm not sure what you mean, could you elaborate? – Enforce Feb 04 '20 at 01:40
In what way do you want to specify it - by a docstring, or a type annotation, or raising a `TypeError` on invalid inputs, or something else? – kaya3 Feb 04 '20 at 01:41
@Enforce Add a type check: `if not isinstance(circle2, Circle): raise TypeError`. – ekhumoro Feb 04 '20 at 01:41
Try ```def intersect(self, circle2: "Circle"): ``` – Lapis Rose Feb 04 '20 at 01:42
@Enforce Are you referring to use [Type Hints](https://docs.python.org/3/library/typing.html) in your question? Python doesn't have any other native way of specifying the type of variables. – Carcigenicate Feb 04 '20 at 01:44
@Lapis Rose That is what I was looking for. I knew I had seen it somwhere but couldn't remember exactly. – Enforce Feb 04 '20 at 01:52

How can I declare the type of variable if it is a class I created? (Python)

0 Answers0