Solution:
This is the MobilePhone class definition:
class MobilePhone:
def __init__(self, display_size, ram, os):
self.display_size = display_size
self.ram = ram
self.os = osThe solution can also be found in the code files for this chapter in the file named mobile_phone1.py.
Solution:
import math
class Circle:
def __init__(self, radius):
self.radius = radius
def area(self):
return math.pi * self.radius ** 2
def circumference(self):
return 2 * math.pi * self.radius
def change_radius(self, new_radius):
self.radius = new_radius
circle = Circle(7)
while True:
radius = float(input("Circle radius: "))
circle.change_radius(radius)
print("Area:", circle.area())
print("Circumference:", circle.circumference())The solution can also be found in the code files for this chapter in the file named circle.py.
Solution:
class Elevator:
occupancy_limit = 8
def __init__(self, occupants):
if occupants > self.occupancy_limit:
print("The maximum occupancy limit has been exceeded."
f" {occupants - self.occupancy_limit} occupants must exit the elevator.")
self.occupants = occupants
elevator1 = Elevator(6)
print("Elevator 1 occupants:", elevator1.occupants)
elevator2 = Elevator(10)
print("Elevator 2 occupants:", elevator2.occupants)The solution can also be found in the code files for this book in the file named elevator.py.
Solution:
class MusicPlayer:
firmware_version = 1.0
def __init__(self):
self.__tracks = ["Moonage Daydream", "Starman", "Life on Mars?"]
self.current_track = None
def play(self):
self.current_track = self.__tracks[0]
def list_tracks(self):
return self.__tracks
@classmethod
def update_firmware(cls, new_version):
if new_version > cls.firmware_version:
cls.firmware_version = new_version
player = MusicPlayer()
print("Tracks currently on device:", player.list_tracks())
MusicPlayer.update_firmware(2.0)
print("Updated player firmware version to", player.firmware_version)
player.play()
print("Currently playing", f"'{player.current_track}'")The solution can also be found in the code files for this course in the file named musicplayer.py.
Solution:
class Cat:
def __init__(self, mass, lifespan, speed):
self.mass_in_kg = mass
self.lifespan_in_years = lifespan
self.speed_in_kph = speed
def vocalize(self):
print("Chuff")
def __str__(self):
return f"The {type(self).__name__.lower()} "\
f"weighs {self.mass_in_kg}kg,"\
f" has a lifespan of {self.lifespan_in_years} years and "\
f"can run at a maximum speed of {self.speed_in_kph}kph."
class Tiger(Cat):
def __init__(self, mass, lifespan, speed):
super().__init__(mass, lifespan, speed)
self.coat_pattern = "striped"
def __str__(self):
facts = super().__str__()
facts = f"{facts} It also has a {self.coat_pattern} coat."
return facts
tiger = Tiger(310, 26, 65)
print(tiger)The solution for this activity can also be found in the tiger.py file in the attached code files for this chapter.
Solution:
class MobilePhone:
def __init__(self, memory):
self.memory = memory
class Camera:
def take_picture(self):
print("Say cheese!")
class CameraPhone(MobilePhone, Camera):
pass
cameraphone = CameraPhone("200KB")
cameraphone.take_picture()
print(cameraphone.memory)The solution for this activity can also be found in the cameraphone.py file in the attached code files for this chapter.