ArrayList: Storing Points - Python Programming Exercise

import math

class Point:
    """A class representing a point in 2D space with X and Y coordinates."""
    
    def __init__(self, x, y):
        """Initialize the point with given X and Y coordinates."""
        self.x = x
        self.y = y

    def __repr__(self):
        """Return a string representation of the point."""
        return f"Point({self.x}, {self.y})"

    def distance_to(self, other_point):
        """Calculate the Euclidean distance from this point to another point."""
        return math.sqrt((self.x - other_point.x) ** 2 + (self.y - other_point.y) ** 2)


class PointCollection:
    """A collection of points that supports adding, removing, displaying points, and finding distances."""
    
    def __init__(self):
        """Initialize the collection as an empty list."""
        self.points = []

    def add_point(self, point):
        """Add a point to the collection."""
        if isinstance(point, Point):
            self.points.append(point)
        else:
            print("Error: Only Point objects can be added.")

    def remove_point(self, point):
        """Remove a point from the collection."""
        try:
            self.points.remove(point)
        except ValueError:
            print("Error: Point not found in the collection.")

    def display_points(self):
        """Display all points in the collection."""
        if not self.points:
            print("No points to display.")
        else:
            for point in self.points:
                print(point)

    def calculate_distance(self, point1, point2):
        """Calculate the distance between two points in the collection."""
        if point1 in self.points and point2 in self.points:
            return point1.distance_to(point2)
        else:
            print("Error: Both points must be in the collection.")
            return None

    def find_closest_point(self, reference_point):
        """Find the point in the collection closest to a given point."""
        if not self.points:
            print("Error: The collection is empty.")
            return None
        closest_point = self.points[0]
        min_distance = reference_point.distance_to(closest_point)
        for point in self.points[1:]:
            distance = reference_point.distance_to(point)
            if distance < min_distance:
                closest_point = point
                min_distance = distance
        return closest_point


# Main function to demonstrate the functionality
def main():
    # Create a PointCollection instance
    collection = PointCollection()

    # Create some points
    point1 = Point(1, 2)
    point2 = Point(3, 4)
    point3 = Point(-1, -1)
    point4 = Point(5, 5)

    # Add points to the collection
    collection.add_point(point1)
    collection.add_point(point2)
    collection.add_point(point3)
    collection.add_point(point4)

    # Display all points
    print("Points in the collection:")
    collection.display_points()

    # Calculate the distance between two points
    print(f"\nDistance between {point1} and {point2}: {collection.calculate_distance(point1, point2)}")

    # Find the closest point to point1
    closest_point = collection.find_closest_point(point1)
    if closest_point:
        print(f"\nThe closest point to {point1} is {closest_point}.")

    # Remove a point from the collection
    collection.remove_point(point3)

    # Display points after removal
    print("\nPoints in the collection after removing one point:")
    collection.display_points()


# Run the program
if __name__ == "__main__":
    main()

 Output

Points in the collection:
Point(1, 2)
Point(3, 4)
Point(-1, -1)
Point(5, 5)

Distance between Point(1, 2) and Point(3, 4): 2.8284271247461903

The closest point to Point(1, 2) is Point(3, 4).

Points in the collection after removing one point:
Point(1, 2)
Point(3, 4)
Point(5, 5)