Objects I
Class objectives
Syntax table
| A class is a code template for creating objects. Objects have member variables and have behaviour associated with them. In python a class is created by the keyword class. An object is created using the constructor of the class. |
What is an object?
In computer science, an object can be a variable, a data structure, a function, or a method, and as such, is a value in memory referenced by an identifier. In the class-based object-oriented programming paradigm, object refers to a particular instance of a class, where the object can be a combination of variables, functions, and data structures.
How to define an object in Python?
from turtle import *
class Car:
def __init__(self, color, brand, model):
self.color = color
self.brand = brand
self.model = model
def draw(self):
pencolor(self.color)
forward(100)
done()
ford = Car('Red', 'Ford', 'Mustang')
print(ford.color, ford.brand, ford.model)
ford.draw()
Objects in game design
Turtle race
Once upon a time, four turtles come together to race. All of them are good at running, therefore, winner of each race is different. Let’s see how does Python make it happen.
from turtle import *
from random import randint
# Basic setup
speed(0)
penup()
goto(-140, 140)
# Draw the road
for step in range(15):
write(step, align='center')
right(90)
for num in range(8):
penup()
forward(10)
pendown()
forward(10)
penup()
backward(160)
left(90)
forward(20)
# Define a turtle function
def ready_turtle(turtle, color, position):
turtle.color(color)
turtle.shape('turtle')
turtle.penup()
turtle.goto(position[0], position[1])
turtle.pendown()
for turn in range(10):
turtle.right(36)
# Create turtles of four different colors
red, blue, green, yellow = Turtle(),Turtle(),Turtle(),Turtle()
ready_turtle(red, 'red', [-160, 100])
ready_turtle(blue, 'blue', [-160, 70])
ready_turtle(green, 'green', [-160, 40])
ready_turtle(yellow, 'yellow', [-160, 10])
# Yeay! Let's begin the race!
for turn in range(100):
red.forward(randint(1,5))
blue.forward(randint(1,5))
green.forward(randint(1,5))
yellow.forward(randint(1,5))
done()
Guessing game
Guess a number from 1 to 99.
import random
random_number = random.randint(1,99)
name = input('Hi, This is robot. What is your name? :')
print('Nice to meet you ' + name)
guess = input('Please guess a number from 1 to 99')
while 1 <= int(guess) <= 99:
if int(guess) < random_number:
print('Guess is too low')
guess = input('Please try again')
elif int(guess) > random_number:
print('Guess is too hight')
guess = input('Please try again')
else:
print('Yeay! You guessed it!')
break
Homework: Draw a phone
Given a class Phone with a function draw_phone. Please write the code to draw an iPhone.
Code skeleton is below:
from turtle import *
class Phone:
def __init__(self, name, brand):
def draw_phone(self):
Output:
