1
status = input("今天是晴天吗？请输入Yes或No: ")
2

3
if status == "Yes":
4
  print("今天副社长石头要去骑车")
5
elif status == "No":
6
  print("今天副社长石头回去看罗小黑哦!喵~")
7
else:
8
  print("你输入的不是Yes或No吧？检查一下哦")

1
n = int(input("请输入一个整数 n："))
2

3
print(f"1 到 {n} 中的所有质数为：")
4

5
for num in range(2, n + 1):
6
    is_prime = True
7
    for i in range(2, int(num ** 0.5) + 1):
8
        if num % i == 0:
9
            is_prime = False
10
            break
11
    if is_prime:
12
        print(num, end=" ")

1
# 比较运算符
2
a = 10
3
b = 5
4
print(a > b)   # True
5
print(a == b)  # False
6
print(a != b)  # True

1
# 完整的 if-elif-else 结构
2
score = int(input("请输入你的分数："))
3

4
if score >= 90:
5
    grade = "A"
6
    print("优秀！")
7
elif score >= 80:
8
    grade = "B"
9
    print("良好！")
10
elif score >= 70:
11
    grade = "C"
12
    print("中等！")
13
elif score >= 60:
14
    grade = "D"
15
    print("及格！")
16
else:
17
    grade = "F"
18
    print("不及格，需要努力！")
19

20
print(f"你的等级是：{grade}")

1
age = int(input("请输入你的年龄："))
2
has_license = input("你有驾照吗？(yes/no): ").lower()
3

4
if age >= 18:
5
    if has_license == "yes":
6
        print("你可以开车上路！")
7
    else:
8
        print("你需要先考取驾照！")
9
else:
10
    print("你还未成年，不能开车！")

1
# and（与）、or（或）、not（非）
2
age = 20
3
is_student = True
4
has_ticket = False
5

6
if age >= 18 and is_student:
7
    print("可以享受学生优惠！")
8

9
if has_ticket or age < 12:
10
    print("可以进入！")
11

12
if not has_ticket:
13
    print("需要购票！")

1
# 基本 while 循环
2
count = 1
3
while count <= 5:
4
    print(f"这是第 {count} 次循环")
5
    count += 1  # 重要：不要忘记改变条件变量！
6

7
# 无限循环与 break
8
total = 0
9
while True:  # 无限循环
10
    num = input("请输入数字（输入'q'退出）：")
11
    if num == 'q':
12
        break  # 跳出循环
13
    total += int(num)
14
print(f"总和为：{total}")
15

16
# continue 的使用
17
num = 0
18
while num < 10:
19
    num += 1
20
    if num % 2 == 0:
21
        continue  # 跳过偶数
22
    print(num)

1
# 遍历列表
2
fruits = ["苹果", "香蕉", "橙子", "葡萄"]
3
for fruit in fruits:
4
    print(f"我喜欢吃{fruit}")
5

6
# 遍历字符串
7
message = "Hello Python"
8
for char in message:
9
    print(char)
10

11
# range() 函数详解
12
print("range(5):", list(range(5)))      # [0, 1, 2, 3, 4]
13
print("range(2, 7):", list(range(2, 7))) # [2, 3, 4, 5, 6]
14
print("range(1, 10, 2):", list(range(1, 10, 2))) # [1, 3, 5, 7, 9]
15

16
# 反向遍历
17
for i in range(10, 0, -1):
18
    print(i, end=" ")  # 10 9 8 7 6 5 4 3 2 1

1
# for-else：当循环正常完成（未被break中断）时执行else
2
for i in range(5):
3
    if i == 10:  # 这个条件永远不会满足
4
        break
5
    print(i)
6
else:
7
    print("循环正常完成！")
8

9
# while-else 类似
10
count = 0
11
while count < 5:
12
    print(count)
13
    count += 1
14
else:
15
    print("while循环正常结束")

1
# 打印乘法表
2
print("九九乘法表：")
3
for i in range(1, 10):
4
    for j in range(1, i + 1):
5
        print(f"{j}×{i}={i*j:2d}", end="  ")
6
    print()  # 换行

1
def is_prime(num):
2
    """判断一个数是否为质数"""
3
    if num <= 1:
4
        return False
5
    if num == 2:
6
        return True
7
    if num % 2 == 0:
8
        return False
9

10
    # 只检查奇数因子
11
    for i in range(3, int(num ** 0.5) + 1, 2):
12
        if num % i == 0:
13
            return False
14
    return True
15

16
def find_primes(n):
17
    """找出1到n中的所有质数"""
18
    primes = []
19
    if n >= 2:
20
        primes.append(2)
21

22
    # 只检查奇数
23
    for num in range(3, n + 1, 2):
24
        if is_prime(num):
25
            primes.append(num)
26

27
    return primes
28

29
# 主程序
30
n = int(input("请输入一个整数 n："))
31
primes = find_primes(n)
32
print(f"1 到 {n} 中的所有质数：{primes}")
33
print(f"共有 {len(primes)} 个质数")

1
def sieve_of_eratosthenes(n):
2
    """使用筛法找出所有质数"""
3
    if n < 2:
4
        return []
5

6
    # 创建标记数组，初始假设所有数都是质数
7
    is_prime = [True] * (n + 1)
8
    is_prime[0] = is_prime[1] = False
9

10
    for i in range(2, int(n ** 0.5) + 1):
11
        if is_prime[i]:
12
            # 将i的倍数标记为非质数
13
            for j in range(i * i, n + 1, i):
14
                is_prime[j] = False
15

16
    # 收集所有质数
17
    primes = [i for i in range(2, n + 1) if is_prime[i]]
18
    return primes
19

20
# 测试筛法
21
n = int(input("请输入一个整数 n："))
22
primes = sieve_of_eratosthenes(n)
23
print(f"1 到 {n} 中的所有质数：")
24
for i, prime in enumerate(primes, 1):
25
    print(f"{prime:4d}", end=" ")
26
    if i % 10 == 0:  # 每行显示10个
27
        print()

1
def prime_factors(num):
2
    """分解质因数"""
3
    factors = []
4
    divisor = 2
5

6
    while divisor * divisor <= num:
7
        if num % divisor == 0:
8
            factors.append(divisor)
9
            num //= divisor
10
        else:
11
            divisor += 1 if divisor == 2 else 2  # 跳过偶数
12

13
    if num > 1:
14
        factors.append(num)
15

16
    return factors
17

18
# 测试质因数分解
19
number = int(input("请输入一个正整数："))
20
factors = prime_factors(number)
21
print(f"{number} = ", end="")
22
print(" × ".join(map(str, factors)))

1
import random
2

3
def guess_number():
4
    """猜数字游戏"""
5
    secret = random.randint(1, 100)
6
    attempts = 0
7
    max_attempts = 10
8

9
    print("猜数字游戏开始！我有一个1-100之间的秘密数字。")
10

11
    while attempts < max_attempts:
12
        try:
13
            guess = int(input(f"第{attempts+1}次尝试，请输入你的猜测："))
14
        except ValueError:
15
            print("请输入有效的数字！")
16
            continue
17

18
        attempts += 1
19

20
        if guess < secret:
21
            print("太小了！")
22
        elif guess > secret:
23
            print("太大了！")
24
        else:
25
            print(f"恭喜！你在{attempts}次内猜对了！")
26
            break
27

28
    if attempts >= max_attempts:
29
        print(f"游戏结束！正确答案是：{secret}")
30

31
# 运行游戏
32
guess_number()

1
def calculator():
2
    """简单的计算器"""
3
    print("简单计算器")
4
    print("支持的操作：+ - * / % **")
5
    print("输入 'quit' 退出")
6

7
    while True:
8
        expression = input("\n请输入表达式：").strip()
9

10
        if expression.lower() == 'quit':
11
            print("再见！")
12
            break
13

14
        try:
15
            result = eval(expression)  # 注意：eval有安全风险，这里仅用于示例
16
            print(f"结果：{result}")
17
        except ZeroDivisionError:
18
            print("错误：不能除以零！")
19
        except:
20
            print("错误：无效的表达式！")
21

22
# 更安全的版本
23
def safe_calculator():
24
    """更安全的计算器版本"""
25
    while True:
26
        print("\n1. 加法")
27
        print("2. 减法")
28
        print("3. 乘法")
29
        print("4. 除法")
30
        print("5. 退出")
31

32
        choice = input("请选择操作：")
33

34
        if choice == '5':
35
            break
36

37
        if choice not in ['1', '2', '3', '4']:
38
            print("无效的选择！")
39
            continue
40

41
        try:
42
            num1 = float(input("请输入第一个数："))
43
            num2 = float(input("请输入第二个数："))
44

45
            if choice == '1':
46
                result = num1 + num2
47
                operator = "+"
48
            elif choice == '2':
49
                result = num1 - num2
50
                operator = "-"
51
            elif choice == '3':
52
                result = num1 * num2
53
                operator = "*"
54
            elif choice == '4':
55
                if num2 == 0:
56
                    print("错误：除数不能为零！")
57
                    continue
58
                result = num1 / num2
59
                operator = "/"
60

61
            print(f"{num1} {operator} {num2} = {result}")
62

63
        except ValueError:
64
            print("请输入有效的数字！")