Day 09 函数基础作业

1. 编写一个函数，求1+2+3+...+N

def num_sum(n):
    sum_num = 0
    for num in range(n+1):
        sum_num += num
    return sum_num


#例子：求1+2+...100
print(num_sum(100))     # 5050

2. 编写一个函数，求多个数中的最大值

def max_num(*nums):
    max_n = nums[0]
    for num in nums:
        if num > max_n:
            max_n = num
    return max_n


# 例子：求2, 36, 67, 99, 33, 44中最大值
print(max_num(2, 36, 67, 99, 33, 44))   # 99

3. 编写一个函数，实现摇骰子的功能，打印n个骰子的点数和

def sum_dice(n):
    import random
    sum_num = 0
    while n:
        num = random.randint(1, 6)
        print(num)  #打印出每次摇骰子的值，便于理解
        sum_num += num
        n -= 1
    return sum_num


# 例子：打印投6次骰子的和
print(sum_dice(6))  # 随机

4. 编写一个函数，交换指定字典的key和value。

def change_num(dict_a):
    dict_b = {}
    for dict_key in dict_a:
        dict_b[dict_a[dict_key]] = dict_key
    return dict_b


#例子
dict1 = {"a": 1, "b": 2, "c": 3}
print(change_num(dict1))     # {1: "a", 2: "b", 3: "c"}

5. 编写一个函数，提取指定字符串中的所有的字母，然后拼接在一起后打印出来

# method_one
def joint_str(str_a):
    str_print = ""
    for str_x in str_a:
        if str_x.isalpha():
            str_print += str_x
    return str_print


# method_two
def joint_str2(str_a):
    str_print2 = ""
    for str_x2 in str_a:
        if ("a" <= str_x2 <= "z") or ("A" <= str_x2 <= "Z"):
            str_print2 += str_x2
    return  str_print2



# 例子：
a = "21werty3abc"
print(joint_str(a))     # wertyabc
print(joint_str2(a))

6. 写一个函数，求多个数的平均值

def average_nums(*n):
    average_num = sum(n) / len(n)
    return  average_num


# 例子：求 5， 10， 15的平均值
print(average_nums(5, 10, 15))      # 10.0

7. 写一个函数，默认求10的阶层，也可以求其他数的阶层

def factorial(n):
    factorial_n = 1
    for num in range(1, n+1):
        factorial_n *= num
    return factorial_n


# 例子：求10的阶乘
print(factorial(10))    # 3628800

8. 写一个函数，可以对多个数进行不同的运算(所有运算都用上)

def operations(mark, num1, *nums):
    sum_nums = num1
    for num in nums:
        if mark == "+":
            sum_nums += num
        elif mark == "-":
            sum_nums -= num
        elif mark == "*":
            sum_nums *= num
        elif mark == "/":
            sum_nums /= num
        elif mark == "//":
            sum_nums //= num
        elif mark == "**":
            sum_nums **= num
    return sum_nums


# 例子：10， 2， 2 之间用+  -  *  /  **  // 运算
print(operations("+", 10, 2, 2))    # 14
print(operations("-", 10, 2, 2))    # 6
print(operations("*", 10, 2, 2))    # 40
print(operations("/", 10, 2, 2))    # 2.5
print(operations("**", 10, 2, 2))   # 10000
print(operations("//", 10, 2, 2))   # 2

9.写一个函数，求指定列表中，指定的元素的个数

def list_count(list_x, n):
    counts_num = list_x.count(n)
    return counts_num


# 例子：a = [1, 2, 1, 2, 1, 2, 3, 4, 1, 1, 1] 求1的个数
a = [1, 2, 1, 2, 1, 2, 3, 4, 1, 1, 1]
print(list_count(a, 1))     # 6

10.写一个函数，获取指定列表中指定元素对应的下标(如果有多个，一起返回)

def index_count(list_x, n):
    list_index = []
    for num in range(len(list_x)):
        if list_x[num] == n:
            list_index.append(num)
    return  list_index


# 例子：a = [1, 2, 2, 1, 2, 3, 4, 1, 1] 求1的下标
a = [1, 2, 2, 1, 2, 3, 4, 1, 1]
print(index_count(a, 1))    #[0, 3, 7, 8]