2018-10-10 day9作业

1. 编写一个函数，求1+2+3+...+N

def my_sum(n):
    sum1 = 0
    for i in range(1,n+1):
        sum1 += i
        return sum1
print(my_sum(100))

2. 编写一个函数，求多个数中的最大值

def my_max(*nums):
    max1 = nums[0]
    for item in nums:
        if item > max1:
            max1 =item
    return max1
print(my_max(13,24,46,77,90))
from random import randint

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 play_dict(n):
    sum1 = 0
    for _ in range(n):
        num = randint(2,6)
        print(num)
        sum1 += num
    return sum1
print(play_dict(4))

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'}

def change_key_value(dict1:dict):
    for key in dict1.copy():
        value = dict1[key]
        del dict1[key]
        dict1[value] = key
dict2 = {'a':1, 'b':2, 'c':3}
change_key_value(dict2)
print(dict2)

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'

def connect(str1:str):
    str2 = ''
    for char in str1:
        if char.isalpha():
            str2 +=char
    return str2
print(connect('12a&bc12d'))

6. 写一个函数，求多个数的平均值

def my_mean(*nums):
    return sum (nums) /len (nums)
print(my_mean(1,3,5,7))

7. 写一个函数，默认求10的阶层，也可以求其他数的阶层

def my_factorial(n=10):
    sum1 = 1
    for i in range(1,n+1):
        sum1 *= i
        return sum1
print(my_factorial(5))
print(my_factorial())

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 my_operation(operator,*nums):
    if operator == '+':
        sum1 = 0
        for num in nums:
            sum1 +=num
        return sum1
    elif operator == '-':
        sum1 =nums[0]
        for index in range(1,len(nums)):
            sum1 -=nums[index]
        return sum1
    elif operator == '*':
        sum1 = 1
        for num in nums:
            sum1 *= num
        return sum1
print(my_operation('+',1,2,3,4))
print(my_operation('-',1,2,3,4))
print(my_operation('*',1,2,3,4))

9.写一个函数，求指定列表中，指定的元素的个数

def my_count(list1:list,item):
    count = 0
    for i in list1:
        if i == item:
            count == 1
        return count
print(my_count([1,2,3,4,7],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 my_index(list1, item):
    indexs = []
    for index in range(len(list1)):
        x =list1[index]
        if x == item:
            indexs.append(index)
        return indexs
print(my_index([1,2,4,7,1,34],1)