python123素数求和31

以下是使用 Python 编写的求素数和的程序： ```python def is_prime(n): """判断一个数是否为素数""" if n < 2: return False for i in range(2, int(n**0.5)+1): if n % i == 0: return False return True def prime_sum(n): """计算小于等于n的所有素数之和""" sum = 0 for i in range(2, n+1): if is_prime(i): sum += i return sum n = int(input("请输入一个正整数：")) print("小于等于", n, "的素数之和为：", prime_sum(n)) ``` 运行程序后，会要求输入一个正整数，然后计算小于等于该数的所有素数之和，并将结果输出。

好的，以下是每个任务的具体实现： ### 1. 输出“Hello, World!” ```python print("Hello, World!") ``` ### 2. 变量赋值 ```python name = "C知道" print(name) ``` ### 3. 数据类型转换 ```python num_str = "123" num_int = int(num_str) print(num_int) ``` ### 4. 简单加法 ```python a = 10 b = 20 sum_ab = a + b print(sum_ab) ``` ### 5. 求余数 ```python remainder = 17 % 5 print(remainder) ``` ### 6. 字符串拼接 ```python greeting = "Hello" name = "Kimi" message = greeting + " " + name print(message) ``` ### 7. 判断奇偶 ```python number = int(input("请输入一个整数: ")) if number % 2 == 0: print(f"{number} 是偶数") else: print(f"{number} 是奇数") ``` ### 8. 比较大小 ```python num1 = float(input("请输入第一个数字: ")) num2 = float(input("请输入第二个数字: ")) max_num = max(num1, num2) print(f"较大的数字是 {max_num}") ``` ### 9. 交换变量值 ```python x = 10 y = 20 x, y = y, x print(f"x 的值为 {x}, y 的值为 {y}") ``` ### 10. 使用`if`语句 ```python number = float(input("请输入一个数字: ")) if number > 0: print("Positive") else: print("Non-positive") ``` ### 11. 使用`elif`语句 ```python number = float(input("请输入一个数字: ")) if number > 0: print("Positive") elif number < 0: print("Negative") else: print("Zero") ``` ### 12. 简单循环 ```python for i in range(1, 11): print(i) ``` ### 13. 求和 ```python total_sum = sum(range(1, 11)) print(total_sum) ``` ### 14. 打印乘法表 ```python for i in range(1, 10): for j in range(1, 10): print(f"{i}*{j}={i*j}", end="\t") print() ``` ### 15. 使用`while`循环 ```python i = 1 while i <= 10: print(i) i += 1 ``` ### 16. 判断素数 ```python def is_prime(n): if n <= 1: return False for i in range(2, int(n**0.5) + 1): if n % i == 0: return False return True number = int(input("请输入一个整数: ")) if is_prime(number): print(f"{number} 是素数") else: print(f"{number} 不是素数") ``` ### 17. 列表操作 ```python my_list = [1, 2, 3, 4, 5] length = len(my_list) print(length) ``` ### 18. 列表切片 ```python my_list = [1, 2, 3, 4, 5] slice_result = my_list[1:4] print(slice_result) ``` ### 19. 列表排序 ```python unsorted_list = [3, 1, 4, 1, 5, 9] sorted_list = sorted(unsorted_list) print(sorted_list) ``` ### 20. 元组操作 ```python my_tuple = (1, 2, 3) second_element = my_tuple[1] print(second_element) ``` ### 21. 字典操作 ```python person_info = {"name": "Kimi", "age": 25} print(person_info["name"]) ``` ### 22. 字典更新 ```python person_info = {"name": "Kimi", "age": 25} person_info["age"] = 26 print(person_info) ``` ### 23. 字符串长度 ```python input_string = input("请输入一个字符串: ") string_length = len(input_string) print(string_length) ``` ### 24. 字符串反转 ```python input_string = input("请输入一个字符串: ") reversed_string = input_string[::-1] print(reversed_string) ``` ### 25. 判断字符串是否包含子串 ```python main_string = input("请输入主字符串: ") sub_string = input("请输入子字符串: ") contains_substring = sub_string in main_string print(contains_substring) ``` ### 26. 使用`range()`函数 ```python numbers = list(range(1, 11)) print(numbers) ``` ### 27. 使用`in`关键字 ```python my_list = [1, 2, 3, 4, 5] is_three_in_list = 3 in my_list print(is_three_in_list) ``` ### 28. 使用`break`语句 ```python for i in range(1, 11): if i == 5: print("Stop") break else: print(i) ``` ### 29. 使用`continue`语句 ```python for i in range(1, 11): if i == 5: continue print(i) ``` ### 30. 简单函数 ```python def add(a, b): return a + b result = add(10, 20) print(result)