import re

email = "example@domain.com"
pattern = r"^[a-zA-Z0-9_.+-]+@[a-zA-Z0-9-]+\.[a-zA-Z0-9-.]+$"
if re.match(pattern, email):
    print("有效的邮箱地址")
else:
    print("无效的邮箱地址")

python复制代码import re

pattern = re.compile(r"\d+")
result = pattern.findall("订单号123，总金额456元")
print(result)  # 输出 ['123', '456']

pattern = re.compile(r"hello", re.IGNORECASE)
print(pattern.findall("Hello, hello, HELLO"))  # 输出 ['Hello', 'hello', 'HELLO']

def demo(a, b, c=3, d=100):
    return sum((a, b, c, d))

print(demo(1, 2, 3, 4))  # (1)
print(demo(1, 2, d=3))   # (2)

10，9

list2 = [5, 6, 7, 8, 9]
print(list2[])       # (1)
print(list2[2:])     # (2)
print(list2[:-2])    # (3)
print(list2[1:3])    # (4)
print(list2[1] <= 3 or list2[3] > 5)  # (5)

# (1) 错误：SyntaxError
# (2) [7, 8, 9]
# (3) [5, 6, 7]
# (4) [6, 7]
# (5) True

import types

class Car:
    price = 100000                               # 定义类属性
    def __init__(self, c):
        self.color = c                           # 定义实例属性

car1 = Car("Red")                                # 实例化对象
car2 = Car("Blue")
print(car1.color, Car.price)                     # 查看实例属性和类属性的值
Car.price = 110000                               # 修改类属性
Car.name = 'QQ'                                  # 动态增加类属性
car1.color = "Yellow"                            # 修改实例属性
print(car2.color, Car.price, Car.name)
print(car1.color, Car.price, Car.name)

Red 100000
Blue 110000 QQ
Yellow 110000 QQ

Dcountry = {
    "中国": "北京",
    "美国": "华盛顿",
    "法国": "巴黎"
}

print(list(Dcountry.values()))  # (1)
print(list(Dcountry.keys()))    # (2)
print(Dcountry.get("德国", "伦敦"))  # (3)
print(Dcountry.get("美国", "伦敦"))  # (4)

for key in Dcountry:  # (5)
    print(key)

['北京', '华盛顿', '巴黎']  # (1)
['中国', '美国', '法国']  # (2)
伦敦  # (3)
华盛顿  # (4)
中国
美国
法国  # (5)

# 设定用户名和密码
username = "admin"
password = "123456"

# 最大尝试次数
max_attempts = 3

# 登录验证
for attempt in range(max_attempts):
    input_username = input("请输入用户名: ")
    input_password = input("请输入密码: ")

    if input_username == username and input_password == password:
        print("登录成功！")
        break
    else:
        remaining_attempts = max_attempts - attempt - 1
        if remaining_attempts > 0:
            print(f"请注意，剩余尝试次数为 {remaining_attempts} 次")
        else:
            print("3次用户名或者密码均有误，请退出程序！")

# 判断奇偶数的子函数
def is_odd(num):
    return num % 2 != 0

# 主函数
def main():
    # 从键盘接受整数输入
    try:
        num = int(input("请输入一个整数: "))
        
        # 判断奇偶数
        if is_odd(num):
            print(f"{num} 是奇数")
        else:
            print(f"{num} 是偶数")
    except ValueError:
        print("请输入有效的整数")

# 调用主函数
if __name__ == "__main__":
    main()

# 判断回文数的函数
def is_palindrome(num):
    return str(num) == str(num)[::-1]

# 主函数
def main():
    while True:
        # 从键盘输入5位数字
        try:
            num = int(input("请输入一个5位数字（输入0退出程序）: "))
            
            if num == 0:
                print("程序退出")
                break
            
            if 10000 <= num <= 99999:  # 判断是否为5位数字
                if is_palindrome(num):
                    print(f"{num} 是回文数")
                else:
                    print(f"{num} 不是回文数")
            else:
                print("请输入一个有效的5位数字！")
        except ValueError:
            print("输入无效，请输入一个数字！")

# 调用主函数
if __name__ == "__main__":
    main()

# 文件路径
file_path = "D:/test.txt"

# 要写入的字符串
text = "Beautiful is better than ugly.\nExplicit is better than implicit."

# 打开文件并写入
with open(file_path, "w") as file:
    file.write(text)

print("文件已成功创建并写入内容。")

import random
import sqlite3
import pandas as pd

# 凯撒加密函数
def caesar_encrypt(text, shift=3):
    return ''.join([chr((ord(char) - ord('a') + shift) % 26 + ord('a')) if char.isalpha() else char for char in text])

# 生成随机信息
def generate_info():
    name = random.choice(['张伟', '李娜', '王磊', '刘敏', '陈静'])
    gender = random.choice(['男', '女'])
    id_number = ''.join([str(random.randint(0, 9)) for _ in range(18)])
    tel = '1' + str(random.randint(3, 9)) + ''.join([str(random.randint(0, 9)) for _ in range(9)])
    address = ''.join(random.choices('abcdefghijklmnopqrstuvwxyz0123456789', k=15))
    return [name, gender, id_number, tel, address]

# 生成50条数据
people_info = [generate_info() for _ in range(50)]

# 对数据进行凯撒加密
shift = 3
encrypted_info = [[caesar_encrypt(field, shift) for field in person] for person in people_info]

# 写入Excel
def write_to_excel(data):
    df = pd.DataFrame(data, columns=['姓名', '性别', '身份证号', '电话号码', '家庭住址'])
    df.to_excel('encrypted_people_info.xlsx', index=False)

# 写入SQLite
def write_to_sqlite(data):
    conn = sqlite3.connect('people_info.db')
    cursor = conn.cursor()
    cursor.execute('''
    CREATE TABLE IF NOT EXISTS people (
        name TEXT, gender TEXT, id_number TEXT, phone_number TEXT, address TEXT)
    ''')
    cursor.executemany('''
    INSERT INTO people (name, gender, id_number, phone_number, address)
    VALUES (?, ?, ?, ?, ?)
    ''', data)
    conn.commit()
    conn.close()

# 执行写入操作
write_to_excel(encrypted_info)
write_to_sqlite(encrypted_info)

print("数据已成功写入 Excel 和 SQLite 数据库。")

import random

# 1. 使用莱布尼茨级数法近似计算 π
def leibniz_formula(n_terms):
    pi_approx = 0
    for i in range(n_terms):
        pi_approx += ((-1) ** i) / (2 * i + 1)
    return 4 * pi_approx

# 2. 使用蒙特卡罗方法近似计算 π
def monte_carlo_pi(n_points):
    inside_circle = 0
    for _ in range(n_points):
        x = random.random()
        y = random.random()
        # 计算点是否在单位圆内
        if x**2 + y**2 <= 1:
            inside_circle += 1
    return 4 * inside_circle / n_points

# 主函数
def main():
    n_terms = 1000000  # 莱布尼茨级数法迭代次数
    n_points = 1000000  # 蒙特卡罗方法随机点数

    # 使用莱布尼茨级数法计算 π
    pi_leibniz = leibniz_formula(n_terms)
    print(f"莱布尼茨级数法计算 π：{pi_leibniz}")

    # 使用蒙特卡罗方法计算 π
    pi_monte_carlo = monte_carlo_pi(n_points)
    print(f"蒙特卡罗方法计算 π：{pi_monte_carlo}")

if __name__ == "__main__":
    main()

python复制代码def calculate_fare(distance, duration):
    # 基本费用
    base_fare = 8.0
    
    # 计算里程费用
    if distance > 3.3:
        distance_fare = (distance - 3.3) * 1.35
    else:
        distance_fare = 0
    
    # 计算时长费用
    if duration > 9:
        duration_fare = (duration - 9) * 0.2
    else:
        duration_fare = 0
    
    # 总车费
    total_fare = base_fare + distance_fare + duration_fare
    return total_fare

# 获取用户输入的实际里程和时长
distance = float(input("请输入实际行驶里程（公里）："))
duration = float(input("请输入实际行驶时长（分钟）："))

# 计算车费
fare = calculate_fare(distance, duration)

# 输出结果
print(f"此次出行的车费为：{fare:.2f} 元")

复制代码请输入实际行驶里程（公里）：4.1
请输入实际行驶时长（分钟）：21
此次出行的车费为：9.68 元

eval(500/10)
输出
50.0

import jieba
s = "中国举办冬奥会"

n = len([ch for ch in s if '\u4e00' <= ch <= '\u9fa5'])  # 统计中文字符数
m = len(list(jieba.cut(s)))  # 统计中文词语数

print("中文字符数为{}，中文词语数为{}。".format(n, m))

val = (3, 4)

type(val)  # 输出 <class 'tuple'>

val = (3,)  # 正确的单元素元组

type(val)  # 输出 <class 'tuple'>

[0, 1, 2, 3, 4]

for s in "python":
    if s == "h":
        continue
    print(s, end="")

pyhon

n = 1

def func(a, b):
    n = b
    return a * b

s = func("Hello~", 2)

print(s, n)

Hello~Hello~ 1

def func(s, i, j):
    if i < j:
        func(s, i+1, j-1)  # 递归调用
        s[i], s[j] = s[j], s[i]  # 交换元素

def main():
    a = [10, 6, 23, -90, 0, 3]
    func(a, 0, len(a)-1)  # 调用函数进行交换
    print(a)

main()

[3, 0, -90, 23, 6, 10]