常用python功能实现

1、冒泡排序

nums = [56,12,45,67,23,5,78,64,345,123,-58,2,1231,-234]
print(nums)

def bubbleSort(nums):
    for i in range(len(nums)-1):    # 这个循环负责设置冒泡排序进行的次数
        for j in range(len(nums)-i-1):  # ｊ为列表下标
            if nums[j] > nums[j+1]:
                nums[j], nums[j+1] = nums[j+1], nums[j]
    return nums

print (bubbleSort(nums))

2、计算x的n次方

def power(x,n):
    s = 1
    while n > 0:
        n = n - 1
        s = s * x
    return s
print(power(2,4))

3、计算 aa + bb + ······

def calc(*numbers):
    sum = 0
    for n in numbers:
        sum = sum + n*n
    return sum

print(calc(1,2,5,6,6,8,9))

4、计算阶乘n!

def factorial(n):
    if n == 0 or n == 1:
        return 1
    else:
        return (n*factorial(n-1))
print(factorial(5))

5、列出当前目录下的所有文件和目录名

import os
def file_name(file_dir):
    for root, dirs, files in os.walk(file_dir):
        print('root_dir:', root)  # 当前目录路径
        print('sub_dirs:', dirs)  # 当前路径下所有子目录
        print('files:', files)  # 当前路径下所有非目录子文件

print (file_name('C:\Windows\AppPatch'))

6、把一个list中所有的字符串变成小写

L = ['Hello','World','IBM','Apple','Python','Which','GOOGLE']
print([s.lower() for s in L])

7、把原字典的键值对颠倒并产生新的字典

dict1 = {"A":"a","B":"b","C":"c","D":"d","E":"e"}
dict2 = {y:x for x,y in dict1.items()}
print(dict2)

8、打印九九乘法表

for i in range(1,10):
    for j in range(1,i+1):
        print("%d*%d=%2d" % (i,j,i*j),end=" ")
    print()

9、列表合并去重

list1 = [2,5,7,89,3,6,7,90]
list2 = [5,7,78,32,45,6,90]
list3 = list1 + list2
print(list3)
print(set(list3))
print(list(set(list3)))