Object has no attribute in python

Question

I am writing a code in pythony, where I want my ball to move on a graph, and save the positions in a list (posx and posy) I made a ball class, but when I call the constructor, I get this error message: 'Ball' object has no attribute 'posx'. This is my code:

class Ball:
    def __init__(self,xvelocity=1, yvelocity=1, inx=1,iny=5, posx=[],posy=[]):
        self.xvelocity=xvelocity
        self.yvelocity=yvelocity
        #giving velocity
        self.inx=inx
        self.iny=iny
        #defining starting position
        self.posx[0]=self.inx
        self.posy[0]=self.iny

        


ball=Ball()

Do you know why this happens? Thank you for your help.

Answer 1

You have to define the attributes posx and posy as lists first. The next question would be if you actually want the position lists passed as argument.

    self.posx = [self.inx]
    self.posy = [self.iny]