Udemy - 100 Days of Code: The Complete Python Pro Bootcamp

Day 3 - Beginner - Control Flow and Logical Operators

22. If / Else and Comparison Operators

# If/else
if condition:
	do A
else:
	do B

# Comparison Operators 比较运算符  
==        # Equal to 等于  
!=        # Not equal to 不等于
>         # Greater than 大于  
<         # Less than 小于  
>=        # Greater than or equal to 大于等于  
<=        # Less than or equal to 小于等于

23. Modulo

# Check Odd or Even
number_to_check = int(input("What is the number you want to check? "))  

if number_to_check % 2 == 0:  
    print("Even")  
else:  
    print("Odd")

24. Nested if statements and elif statements

# Nested if statements
if condition1:
	do A
	if condition2:
		do B
		if condition3:
			do C

# If/elif/else
if condition1:
	do A
elif condition2:
	do B
else:
	do C

25. Multiple if statements

# Multiple if statements
if condition1:
	do A
if condition2:
    do B
if condition3:
    do C

26. Pizza Order Practice

print("Welcome to Python Pizza Deliveries!")  
size = input("What size pizza do you want? S, M or L: ")  
pepperoni = input("Do you want pepperoni on your pizza? Y or N: ")  
extra_cheese = input("Do you want extra cheese? Y or N: ")  

bill = 0 
  
# todo: work out how much they need to pay based on their size choice.  
if size == "S":  
    bill += 15  
elif size == "M":  
    bill += 20  
elif size == "L":  
    bill += 25  
else:  
    print("You have chosen an invalid size.")  
  
# todo: work out how much to add to their bill based on their pepperoni choice.  
if pepperoni == "Y":  
    if size == "S":  
        bill += 2  
    else:  
        bill += 3  
  
# todo: work out their final amount based on whether if they want extra cheese.  
if extra_cheese == "Y":  
    bill += 1  

print(f"Your final bill is: ${bill}.")

27. Logical Operators

# Logical Operators 逻辑运算符
A and B        # Returns True if both statements are true 与
C or D         # Returns True if one of the statements is true 或
not E          # Returns True if the statement is false 非

28. Treasure Island Project

Demo

print("Welcome to Treasure Island.")
print("Your mission is to find the treasure.")
choice1 = input('You\'re at a crossroad, where do you want to go? '
                'Type "left" or "right".\n').lower()

if choice1 == "left":
    choice2 = input('You\'ve come to a lake. '
                    'There is an island in the middle of the lake. '
                    'Type "wait" to wait for a boat. '
                    'Type "swim" to swim across.\n').lower()
    if choice2 == "wait":
        choice3 = input("You arrive at the island unharmed. "
                        "There is house with 3 doors. One red, "
                        "one yellow and one blue. "
                        "Which colour do you choose?\n").lower()
        if choice3 == "red":
            print("It's a room full of fire. Game Over")
        elif choice3 == "yellow":
            print("You found the treasure. You Win!")
        elif choice3 == "blue":
            print("You enter a room of beasts. Game Over.")
        else:
            print("You chose a door that doesn't exist. Game Over.")
    else:
        print("You got attacked by an angry trout. Game Over.")
else:
    print("You fell in to a hole. Game Over.")