Learn Encapsulation by Building a Projectile Trajectory Calculator - Step 24

Python
1

I’m also having trouble with this. Ive tried doing the code in multiple ways. Heres my current code:

import math

GRAVITATIONAL_ACCELERATION = 9.81
PROJECTILE = "∙"
x_axis_tick = "T"
y_axis_tick = "⊣"

class Projectile:
    __slots__ = ('__speed', '__height', '__angle')

    def __init__(self, speed, height, angle):
        self.__speed = speed
        self.__height = height
        self.__angle = math.radians(angle)
        
    def __str__(self):
        return f'''
Projectile details:
speed: {self.speed} m/s
height: {self.height} m
angle: {self.angle}°
displacement: {round(self.__calculate_displacement(), 1)} m
'''

    def __calculate_displacement(self):
        horizontal_component = self.__speed * math.cos(self.__angle)
        vertical_component = self.__speed * math.sin(self.__angle)
        squared_component = vertical_component**2
        gh_component = 2 * GRAVITATIONAL_ACCELERATION * self.__height
        sqrt_component = math.sqrt(squared_component + gh_component)
        
        return horizontal_component * (vertical_component + sqrt_component) / GRAVITATIONAL_ACCELERATION
        
    def __calculate_y_coordinate(self, x):
        height_component = self.__height
        angle_component = math.tan(self.__angle) * x
        acceleration_component = GRAVITATIONAL_ACCELERATION * x ** 2 / (
                2 * self.__speed ** 2 * math.cos(self.__angle) ** 2)
        y_coordinate = height_component + angle_component - acceleration_component

        return y_coordinate
    
    def calculate_all_coordinates(self):
        return [
            (x, self.__calculate_y_coordinate(x))
            for x in range(math.ceil(self.__calculate_displacement()))
        ]

    @property
    def height(self):
        return self.__height

    @property
    def angle(self):
        return round(math.degrees(self.__angle))

    @property
    def speed(self):
        return self.__speed

    @height.setter
    def height(self, n):
        self.__height = n

    @angle.setter
    def angle(self, n):
        self.__angle = math.radians(n)

    @speed.setter
    def speed(self, s):
       self.__speed = s
    
    def __repr__(self):
        return f'{self.__class__}({self.speed}, {self.height}, {self.angle})'

class Graph:
    __slots__ = ('__coordinates')

    def __init__(self, coord):
        self.__coordinates = coord

    def __repr__(self):
        return f"Graph({self.__coordinates})"

    def create_coordinates_table(self):
        table = '\n  x      y\n'
        for x, y in self.__coordinates:
            table += f'{x:>3}{y:>7.2f}\n'

        return table

    def create_trajectory(self):

        rounded_coords = [(round(x), round(y)) for x, y in self.__coordinates]

        x_max = max(rounded_coords, key=lambda i: i[0])[0]
        y_max = max(rounded_coords, key=lambda j: j[1])[1]

        matrix_list = [[" " for _ in range(x_max + 1)] for _ in range(y_max + 1)]

        for x, y in rounded_coords:
            matrix_list[-1 - y][x] = PROJECTILE

        matrix = ["".join(line) for line in matrix_list]

        matrix_axes = [y_axis_tick + row for row in matrix]
        matrix_axes.append(" " + x_axis_tick * (len(matrix[0])))

        graph = "\n" + "\n".join(matrix_axes) + "\n"

        return graph





def projectile_helper(speed, height, angle):
    projectile = Projectile(speed, height, angle)
    coordinates = projectile.calculate_all_coordinates()
    graph = Graph(coordinates) 
    print(projectile)
    print(graph.create_coordinates_table())   
    print(graph.create_trajectory())
2

when you ask for help please include the link step. If you use the Help button it would do that automatically.

What do the failing tests say?

1 Like
3

Hi @juicethekidd

You should call the projectile_helper function at least once.

Try calling the new function.

Happy coding

1 Like
4
5

Ok my console said my prints weren’t in the right order and I fixed it but its not reading my call

import math

GRAVITATIONAL_ACCELERATION = 9.81
PROJECTILE = "∙"
x_axis_tick = "T"
y_axis_tick = "⊣"

class Projectile:
    __slots__ = ('__speed', '__height', '__angle')

    def __init__(self, speed, height, angle):
        self.__speed = speed
        self.__height = height
        self.__angle = math.radians(angle)
        
    def __str__(self):
        return f'''
Projectile details:
speed: {self.speed} m/s
height: {self.height} m
angle: {self.angle}°
displacement: {round(self.__calculate_displacement(), 1)} m
'''

    def __calculate_displacement(self):
        horizontal_component = self.__speed * math.cos(self.__angle)
        vertical_component = self.__speed * math.sin(self.__angle)
        squared_component = vertical_component**2
        gh_component = 2 * GRAVITATIONAL_ACCELERATION * self.__height
        sqrt_component = math.sqrt(squared_component + gh_component)
        
        return horizontal_component * (vertical_component + sqrt_component) / GRAVITATIONAL_ACCELERATION
        
    def __calculate_y_coordinate(self, x):
        height_component = self.__height
        angle_component = math.tan(self.__angle) * x
        acceleration_component = GRAVITATIONAL_ACCELERATION * x ** 2 / (
                2 * self.__speed ** 2 * math.cos(self.__angle) ** 2)
        y_coordinate = height_component + angle_component - acceleration_component

        return y_coordinate
    
    def calculate_all_coordinates(self):
        return [
            (x, self.__calculate_y_coordinate(x))
            for x in range(math.ceil(self.__calculate_displacement()))
        ]

    @property
    def height(self):
        return self.__height

    @property
    def angle(self):
        return round(math.degrees(self.__angle))

    @property
    def speed(self):
        return self.__speed

    @height.setter
    def height(self, n):
        self.__height = n

    @angle.setter
    def angle(self, n):
        self.__angle = math.radians(n)

    @speed.setter
    def speed(self, s):
       self.__speed = s
    
    def __repr__(self):
        return f'{self.__class__}({self.speed}, {self.height}, {self.angle})'

class Graph:
    __slots__ = ('__coordinates')

    def __init__(self, coord):
        self.__coordinates = coord

    def __repr__(self):
        return f"Graph({self.__coordinates})"

    def create_coordinates_table(self):
        table = '\n  x      y\n'
        for x, y in self.__coordinates:
            table += f'{x:>3}{y:>7.2f}\n'

        return table

    def create_trajectory(self):

        rounded_coords = [(round(x), round(y)) for x, y in self.__coordinates]

        x_max = max(rounded_coords, key=lambda i: i[0])[0]
        y_max = max(rounded_coords, key=lambda j: j[1])[1]

        matrix_list = [[" " for _ in range(x_max + 1)] for _ in range(y_max + 1)]

        for x, y in rounded_coords:
            matrix_list[-1 - y][x] = PROJECTILE

        matrix = ["".join(line) for line in matrix_list]

        matrix_axes = [y_axis_tick + row for row in matrix]
        matrix_axes.append(" " + x_axis_tick * (len(matrix[0])))

        graph = "\n" + "\n".join(matrix_axes) + "\n"

        return graph


def projectile_helper(speed, height, angle):
    projectile = Projectile(speed, height, angle)
    coordinates = projectile.calculate_all_coordinates()
    graph = Graph(coordinates) 
    print(projectile)
    print(graph.create_coordinates_table())
    print(graph.create_trajectory())
    return(projectile_helper)

    projectile_helper(20, 230, 45)
6

You need to call the function from outside the function, not within the function.

Also, nothing in the function after “return” is going to execute. This function does not need to return anything, only print.

1 Like