在学习过程中会不断更新

注意：笔记是为了学习，只记需要的即可，没必要每句话都记下，必要时可自己延申

若笔记可能出现对其理解不深入，不完整，甚至也会出现错误有问题的地方，希望大家谅解、留言提出指正，同时也欢迎大家来找我一起交流学习！

ctrl + / 是多行注释

1.
print("      *      " * 4)
print("    *   *    " * 4)
print("  *       *  " * 4)
print("    *   *    " * 4)
print("      *      " * 4)

2.
name = "John Smith"
age = 20
id = "a new patient"
print(f"We check in a patient named {name}. He's {age} years old and is {id}")

3.
name = input("What's your name?\n")
color = input("What's your favorite color?\n")
print(f"Hi, {name}. I know your favorite color is {color}.")

4.
birth_year = input("What's your birth year?\n")
print(type(birth_year))
age = 2022 - int(birth_year)
print(type(age))
sentence = f"you are {str(age)} years old"
print(sentence)
bool()
float()

5.
weight_catty = input("What's your weight in catty")
weight_kg = float(weight_catty) / 2
print(str(weight_kg))

6.
sentence = "I 'love' you"
sen = 'I "love" you'
print(sentence)
print(sen)
another = sen[:]
ano = sen
# 这两种方法可以用来拷贝复制文字
print(sen[-1] + "  " + sen[0] + "   " + sen[3:7] + "   " + sen[3:] + "   " + sen[:5] + "  " + sen[1:-1])
# sen[-1]，负数是倒着数的；sen[0:5]，从0-4，不输出5;sen[3:], 从3到最后；sen[:5]， 从0到5;sen[1:-1]， 从1直接到导数第二个
print(another)
print(ano)
mail = '''
Hi, John.
Here is our first email to you.
thank you,
The support team.
'''
print(mail)

7.
mail = '''
Hi, John.
Here is our first email to you.
thank you,
The support team.
'''
print(len(mail))
print(mail.upper())
print(mail.lower())
# 以上两个形式不会改变原始字符
print(mail.replace("thank you", "Thank you"))
# 替换相应的文字
print(mail.find('o'))
# 查找字符并返回相应的索引 ，只查找第一个
print("support" in mail)
print("Support" in mail)
# 返回一个bool值，判断“support”是否在mail中

8.
num = 10 / 3
# 输出直接结果，带小数
num_1 = 10 // 3
# 输出取整之后的结果
num_2 = 10 % 3
# 输出余数
num_3= 10 ** 3
# 输出幂
num_4 = 2.5
num_5 = -2.9
print(num)
print(num_1)
print(num_2)
print(num_3)
print(round(num_4))
# 圆函数，用于数字的四舍五入
print(abs(num_5))
# 绝对值函数

9.
import math
print(math.ceil(2.9))
# 返回数字的上入整数
print(math.floor(2.9))
# 返回数字的下舍整数
# 去看官方文档，学习剩下的函数

10.
# if语句
is_not = False
is_cold = False
if is_not:
    print("It's a hot day!")
    print("Drink more water.")
elif is_cold:
    print("It's a cold day!")
    print("Ware warm clothes.")
else:
    print("It's a lovely day.")
print("Enjoy your day.")

11.
price = 1000000
credit = input("If buyer have good credit?(T or F)")
if credit == 'T':
    print("They need to put down 20%.")
    print("They need to pay " + str(price * 0.8))
elif credit == 'F':
    print("They need to put down 10%.")
    print("They need to pay " + str(price * 0.9))
else:
    print("It's wrong.")
# 任何非空字符串输入都将为真
# 两个布尔值都不等于字符串"True"或"False"。
# 直接使用==来判断会更好

12.
price = 1000000
credit = input("If buyer have good credit?(T or F)")
money = input("If buyer have money?(T or F)")
if credit == 'T' and money == 'F':
    print("They need to put down 30%.")
    print("They need to pay " + str(price * 0.7))
elif credit == 'F' and money == 'T':
    print("They need to put down 20%.")
    print("They need to pay " + str(price * 0.8))
else:
    print("They need to put down 10%.")
    print("They need to pay " + str(price * 0.9))


price = 1000000
credit = input("If buyer have good credit?(T or F)")
money = input("If buyer have money?(T or F)")
if credit == 'T' and not money == 'F':
    print("They need to put down 30%.")
    print("They need to pay " + str(price * 0.7))
elif credit == 'F' and not money == 'T':
    print("They need to put down 20%.")
    print("They need to pay " + str(price * 0.8))
else:
    print("They need to put down 10%.")
    print("They need to pay " + str(price * 0.9))

13.
weight = int(input("Weight: "))
unit = input("(L)bs or (K)g: ")
if unit.upper() == 'L':
    convert = weight * 0.45
    print(f"You are {convert} kilos")
else:
    convert = weight / 0.45
    print(f"You are {convert} pounds")
# 选中变量，点击重构，重命名，即可整体改变变量的名称

14.
secret_num = 7
guess_count = 0
guess_limit = 3
while guess_count < guess_limit:
    guess = int(input("Guess: "))
    guess_count += 1
    if guess == secret_num:
        print("You won!")
        break
else:
    print("Sorry, you failed")

15.
command = "" # 空字符
while True:
    command = input("please enter tne problem: ").lower()   # 防止重复，可以直接输入时将其改为小写
    if command == "start":
        print("Started")
    elif command == "stop":
        print("Stopped")
    elif command == "help":
        print('''
    go out
    wait for help
        ''')
    elif command == "quit":
        break
    else:
        print("I can't understand.")

16.
for item in ['john', 'dad', 'mom']:
    print(item)
for item in range(1, 11):   # 打印的是1-10
    print(item)
for item in range(1, 30, 4):  # 从1-29， 每隔4个打印一次
    print(item)
for x in range(5):
    for y in range(4):
        print(f"({x}, {y})")
numbers = [5, 2, 5, 2, 2]
for count in numbers:
    output = ''
    for count in range(count):
        output += 'x'
    print(output)

17.
names = ["John", "Mimi", "Kite"]
print(names)    # outcome is ['John', 'Mimi', 'Kite']
print(names[0])
print(names[2])
print(names[-2])
print(names[1:])  # outcome is ['Mimi', 'Kite']
names[0] = "Joh"
print(names)

18.
# To find the largest number in a list
numbers = [2, 4, 6, 39, 50, 27]
max = numbers[0]
for number in numbers:
    if number > max:
        max = number
print(max)

19.
matrix = [
    [2, 3, 4],
    [5, 6, 7],
    [8, 9, 10]
]
matrix[0][2] = 69
print(matrix[0][2])
for row in matrix:
    for num in row:
        print(num)

20.
numbers = [5, 6, 3, 6, 8]
numbers2 = numbers.copy()  # 拷贝
numbers.append(50)
numbers.insert(3, 40)  # The one number is index
numbers.remove(8)
numbers.pop()  # remove the last number
# number.clear()  # Empty the list
print(numbers)
print(numbers.index(3))  # find the number's index
print(4 in numbers)  # No errors are generated, return Bool value
print(6 in numbers)
print(numbers.count(6))  # Calculate the quantity of number
numbers.sort()  # sort the list
print(numbers)
numbers.reverse()  # 使用sort后再逆向，即可倒序
print(numbers)
print(numbers2)

21.
# 删除一个列表中重复的数字
numbers = [2, 2, 4, 6, 8, 9, 8, 10]
uniques = []
for num in numbers:
    if num not in uniques:
        uniques.append(num)
print(uniques)

# 元组Tuples, 无法修改
numbers = (2, 4, 5)
print(numbers)
print(numbers.count(4))
print(numbers.index(2))

22.
coordinates = (1, 2, 3)
x, y, z = coordinates
# x = coordinates[0]
# y = coordinates[1]
# z = coordinates[2]
coordinates = [1, 2, 3]
l, n, m = coordinates
print(x)
print(l)

23.
# 字典
customer = {
    "name": "John",
    "age": 30,
    "is_verified": True
}
customer["age"] = 19
print(customer.get("name"))  # 使用get防止没有特征时报错
print(customer.get("age"))
print(customer.get("birthdate"))  # None
print(customer.get("birthdate", "2003.9.21"))  # 这样就可以得到一个值 or
customer["birthdate"] = "Jun 1 1998"
print(customer.get("birthdate"))  # {'name': 'John', 'age': 19, 'is_verified': True, 'birthdate': 'Jun 1 1998'}
print(customer)

24.
# 把电话号码换成英文
phone = input("please enter your phone number: ")
digits_mapping = {
    "1": "One",
    "2": "Two",
    "3": "Three",
    "4": "Four",
    "5": "Five",
    "6": "Six",
    "7": "Seven",
    "8": "Eight",
    "9": "Nine",
    "0": "Zero"
}
output = ""
for num in phone:
    print(digits_mapping.get(num, "!"))  # "!"在输入的东西不存在于键值对中时输出！
    output += digits_mapping.get(num, "!") + " "
print(output)   # 用这种方法，就可以把东西打印到一行上 ## 很好用

25.
message = input("> ")
words = message.split(" ")  # split 通过指定分隔符对字符串进行切片
emoji = {
    ":)": "🙂",
    ":(": "☹"
}
output = ""
for word in words:
    output += emoji.get(word, word) + " "     # emoji.get(word, word) 当word是表情，返回表情；是文字，返回文字本身
print(output)

26.
def greet_user(first_name, last_name):
    print(f"{first_name} {last_name}")


greet_user("John", "Smith")  # 距离上面的要有两行的距离
greet_user(last_name="Smith", first_name="Mimi")  # 这样在使用起来更直观

27.
def square(number):
    return number * number


number = int(input(">"))
print(square(number))

28.
def putout(message):
    words = message.split(" ")
    emoji = {
        ":)": "🙂",
        ":(": "☹"
    }
    output = ""
    for word in words:
        output += emoji.get(word, word) + " "
    return output


messages = input("> ")
print(putout(messages)) 作者：Aurora_____W https://www.bilibili.com/read/cv18096128?spm_id_from=333.999.0.0 出处：bilibili