1. 编写一个函数，求1+2+3+...+N

def jie_cheng(num):
    sum = 1
    for x in range(1, num+1):
        sum *= x

    return sum

sum1= jie_cheng(9)
print(sum1)
# 362880

2. 编写一个函数，求多个数中的最大值

def max_num(*num):
   list = []
   list.append(num)
   num1 = 0
   for x in list[0]:
       if x > num1:
           num1 = x
   return num1

num2 = max_num(12,43,321,215)
print(num2) # 321

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

import random
def sum1(n):
    sum2=0
    for x in range(n):
        y = random.randint(1,7)
        sum2+=y
    return sum2
print(sum1(8))
33 14 31

4. 编写一个函数，交换指定字典的key和value。

#  如:{'a':1, 'b':2, 'c':3} ---> {1:'a', 2:'b', 3:'c'}
dict1={'a': 1, 'b': 2, 'c': 3}
def dict_x(dict):
    num=0
    dict2 = {}
    key = []
    value=[]
    for x in dict:
        key.append(dict[x])
        value.append(x)
        num+=1
    for x in range(num):
        dict2[key[x]]=value[x]
    print(dict2)
dict_x(dict1)

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

#  如:'12a&bc12d--' ---> 打印'abcd'
str1 = '12a&bc12d--'
def get_letter():
    str2 = ''
    for x in str1:
        if 'a' <= x <= 'z':
            str2 += x
    return str2
print(get_letter())

6. 写一个函数，求多个数的平均值

def mean(*num):
    list1 = []
    num1 = 0
    for x in num:
        list1.append(x)
    for x in list1:
        num1 += x
    mean = num1/len(list1)
    return mean
print(mean(1,2,3,4,5,10))

7. 写一个函数，默认求10的阶层，也可以求其他数的阶层

def jx_num(a=10):
    x = 1
    for y in range(1,a+1):
            x *=y
    return x
print(jx_num())

8. 写一个函数，可以对多个数进行不同的运算

如: operation('+', 1, 2, 3) ---> 求 1+2+3的结果 operation('-', 10, 9) ---> 求 10-9的结果 operation('', 2, 4, 8, 10) ---> 求 24810的结构

#  def all_num(a,*num):
#      if a == '+':
#          sum1 = 0
#          for x in num:
#              sum1 += x
#      elif a == '-':
#          list1=[]
#          for x in num:
#              list1.append(x)
#          sum1 = list[0] - list[1]
#      elif a == '*':
#          list1 = []
#          for x in num:
#              list1.append(x)
#          for x in list[:]:
#              if

9.写一个函数，求指定列表中，指定的元素的个数

def find_x(a,b):
    count = 0
    for x in a[:]:
        if x == b:
            count += 1
    return count

print(find_x([1,2,3,3,3,4,2,1], 3))

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 find_x(a,b):
    count = 0
    list1 = []
    for x in a[:]:
        if x == b:
            list1.append(count)
        count += 1
    return list1
print(find_x([1,2,3,3,3,4,2,1], 2))