def my_sum(n):
"""
求1+2+3+...+N
"""
sum1 = 0
for i in range(1,n+1):
sum1 += i
print(sum1)

def my_max_n(n):
"""
求多个数中的最⼤大值
"""
num1 =[]
for _ in range(n):
i= int(input("请输入数字:"))
num1.append(i)
return max(num1)

def roll_dice(n):
"""
实现摇⾊色⼦子的功能，打印n个⾊色⼦子的点数
"""
import random
sum1 = 0
for count in range(n):
roll = random.randint(1 , 6)
print("点数%d: %d" % (count, roll))
sum1 += roll
return "点数和: %d" % sum1

def exchange(dict1):
    """
     交换指定字典的key和value
    """
    dict2 = {}
    for key in dict1:
        dict2.update({dict1[key]: key})
    return dict2


def my_max_3(x, y, z):
    """
     求三个数中的最⼤大值
    """
    return max([x, y, z])


def extract_alpha(str1):
    """
     提取指定字符串串中的所有的字⺟母，然后拼接在⼀一起后打印出来
    """
    str2 = ''
    for str3 in str1:
        if str3.isalpha():
            str2 += str3
    print(str2)


def my_average(n):
    """
    求多个数的平均值
    """
    sum1 = 0
    for _ in range(n):
        i= int(input("请输入数字:"))
        sum1 += i
    return sum1 / n

def factorial(n=10):
    """
     默认求10的阶层，也可以求其他数的阶层
    """
    factorial1 = 1
    if n == 10:
        for count in range(1, 11):
            factorial1 *= count
        return factorial1
    else:
        for count in range(1, n + 1):
            factorial1 *= count
        return factorial1


def operation(str1, list1):
    """
    可以对多个数进行不同的运算
    """
    if str1 == '+':
        sum1 = 0
        for index in list1:
            sum1 += list1[index]
        return  sum1
    elif str1 == '-':
        sum1 = 0
        for index in list1:
            sum1 -= list1[index]
        return sum1 + list1[0]*2
    elif str1 == '*':
        sum1 = 1
        for index in list1:
            sum1 *= list1[index]
        return sum1
    elif str1 == '/':
        sum1 = 1
        for index in list1:
            sum1 /= list1[index]
        return sum1 * list1[0]**2