Exercises

  1. Add a distanceFromPoint method that works similar to distanceFromOrigin except that it takes a Point as a parameter and computes the distance between that point and self.


    


      

    

     (classes_q1) 
    




    


    

    

    


    






    

    

    

     
    1
    import math
    2
    ​
    3
    class Point:
    4
        """ Point class for representing and manipulating x,y coordinates. """
    5
    ​
    6
        def __init__(self, initX, initY):
    7
            """ Create a new point at the given coordinates. """
    8
            self.x = initX
    9
            self.y = initY
    10
    ​
    11
        def getX(self):
    12
            return self.x
    13
    ​
    14
        def getY(self):
    15
            return self.y
    16
    ​
    17
        def distanceFromOrigin(self):
    18
            return ((self.x ** 2) + (self.y ** 2)) ** 0.5
    19
    ​
    20
        def distanceFromPoint(self, otherP):
    21
            dx = (otherP.getX() - self.x)
    22
            dy = (otherP.getY() - self.y)
    23
            return math.sqrt(dy**2 + dx**2)
    24
    ​
    25
    p = Point(3, 3)
    26
    q = Point(6, 7)
    27
    print(p.distanceFromPoint(q))
    28
    ​
    

    


    

    

    

    

    


      

    

     (ch_cl_ex_1_answer) 
    




    


    

Show Comments


    
    
    
    

    2. 

  2. Add a method reflect_x to Point which returns a new Point, one which is the
reflection of the point about the x-axis.  For example,
Point(3, 5).reflect_x() is (3, -5)
    


    

    


    













    

    



    

    

    

    

    


      

    

     (ch_cl_02) 
    




    


    3. 

  3. Add a method slope_from_origin which returns the slope of the line joining the origin
to the point.   For example,
    

    >>> Point(4, 10).slope_from_origin()
2.5

    

    

    What cases will cause your method to fail? Return None when it happens.
    


    

    


    













    

    



    

    

    

    

    


      

    

     (classes_q3) 
    




    


    

    

    


    






    

    

    

    27
     
    1
    class Point:
    2
        """ Point class for representing and manipulating x,y coordinates. """
    3
    ​
    4
        def __init__(self, initX, initY):
    5
            """ Create a new point at the given coordinates. """
    6
            self.x = initX
    7
            self.y = initY
    8
    ​
    9
        def getX(self):
    10
            return self.x
    11
    ​
    12
        def getY(self):
    13
            return self.y
    14
    ​
    15
        def distanceFromOrigin(self):
    16
            return ((self.x ** 2) + (self.y ** 2)) ** 0.5
    17
    ​
    18
        def slope_from_origin(self):
    19
            if self.x == 0:
    20
               return None
    21
            else:
    22
               return self.y / self.x
    23
    ​
    24
    ​
    25
    p = Point(4, 10)
    26
    print(p.slope_from_origin())
    27
    ​
    

    


    

    

    

    

    


      

    

     (ch_cl_ex_3_answer) 
    




    


    

Show Comments


    
    
    
    

    4. 

  4. The equation of a straight line is  “y = ax + b”, (or perhaps “y = mx + c”).
The coefficients a and b completely describe the line.  Write a method in the
Point class so that if a point instance is given another point, it will compute the equation
of the straight line joining the two points.  It must return the two coefficients as a tuple
of two values.  For example,
    

    >>> print(Point(4, 11).get_line_to(Point(6, 15)))
>>> (2, 3)

    

    

    This tells us that the equation of the line joining the two points is “y = 2x + 3”.
When will your method fail?
    


    

    


    













    

    



    

    

    

    

    


      

    

     (ch_cl_04) 
    




    


    5. 

  5. Add a method called move that will take two parameters, call them dx and dy.  The method will
cause the point to move in the x and y direction the number of units given. (Hint: you will change the values of the
state of the point)
    


    

    


    













    

    



    

    

    

    

    


      

    

     (classes_q5) 
    




    


    

    

    


    






    

    

    

    30
     
    1
    class Point:
    2
        """ Point class for representing and manipulating x,y coordinates. """
    3
    ​
    4
        def __init__(self, initX, initY):
    5
            """ Create a new point at the given coordinates. """
    6
            self.x = initX
    7
            self.y = initY
    8
    ​
    9
        def getX(self):
    10
            return self.x
    11
    ​
    12
        def getY(self):
    13
            return self.y
    14
    ​
    15
        def distanceFromOrigin(self):
    16
            return ((self.x ** 2) + (self.y ** 2)) ** 0.5
    17
    ​
    18
        def move(self, dx, dy):
    19
            self.x = self.x + dx
    20
            self.y = self.y + dy
    21
    ​
    22
        def __str__(self):
    23
            return str(self.x) + "," + str(self.y)
    24
    ​
    25
    ​
    26
    p = Point(7, 6)
    27
    print(p)
    28
    p.move(5, 10)
    29
    print(p)
    30
    ​
    

    


    

    

    

    

    


      

    

     (ch_cl_05_answer) 
    




    


    

Show Comments


    
    
    
    

    6. 

  6. Given three points that fall on the circumference of a circle, find the center and radius of the circle.
    


    

    


    













    

    



    

    

    

    

    


      

    

     (classes_q6) 
    




    


    7. 






  
      
  
  
  
  
  Next Section - Fractions