Python的一些例题

1.用递归遍历文件夹，如果是文件，打印出路径，如果是目录，继续循环打开

import os
def allfiles(path):
    for i in os.listdir(path):
        filepath=os.path.join(path,i)
        if os.path.isfile(filepath):
            print(filepath)
        else:
            allfiles(filepath)
filepath=os.getcwd()
allfiles("文件")
2，用装饰器计算函数运行时间

import time

def A(a):

   def B():
       start =time.time()
       a()                                    
       end = time.time()
       print(end - start)
   return B
@A
def func1():
   for i in range(1000000):
       type("hello")
func1()
@A
def func2():
   for i in range(1000000):
       isinstance('hello',str)
func2()

3.正则验证IP地址

import re
a = '255.255.255.255'
b = '0.10.99.255'
c = '192.188.0.1'
d = '200.249.254.110'
e = '256.256.256.256'
try:
  resa = re.search('((2(5[0-5]|[0-4]\d))|[0-1]?\d{1,2})(\.((2(5[0-5]|[0-4]\d))|[0-1]?\d{1,2})){3}',a).group()
  print(resa)
  resb = re.search('((2(5[0-5]|[0-4]\d))|[0-1]?\d{1,2})(\.((2(5[0-5]|[0-4]\d))|[0-1]?\d{1,2})){3}', b).group()
  print(resb)
  resc = re.search('((2(5[0-5]|[0-4]\d))|[0-1]?\d{1,2})(\.((2(5[0-5]|[0-4]\d))|[0-1]?\d{1,2})){3}', c).group()
  print(resc)
  resd = re.search('((2(5[0-5]|[0-4]\d))|[0-1]?\d{1,2})(\.((2(5[0-5]|[0-4]\d))|[0-1]?\d{1,2})){3}', d).group()
  print(resd)
  rese = re.search('((2(5[0-5]|[0-4]\d))|[0-1]?\d{1,2})(\.((2(5[0-5]|[0-4]\d))|[0-1]?\d{1,2})){3}', e).group()
  print(rese)
except:
   print('地址不对')
4.注册和登陆程序（封装成类）

class login:
   def __init__(self,id,mima):
       self.id = id
       self.mima = mima
   def judgment2(self):    #登陆程序，经过judgment1(self):以后，要么在judgment1(self):已经退出，要么就一定有账号，循环登录
       f2 = open('users', 'r', encoding='utf-8')
       x2 = eval(f2.read())
       while True:
           name2 = input('用户名:   ')
           password2 = input('密码:    ')
           if (name2, password2) in x2.items():
               f2.close()
               break
           else:
               print('用户名或密码错误请重新输入')
               choice = int(input('重新登陆请输入1,退出请输入2:   '))
               if choice == 1:
                   continue
               elif choice == 2:
                   f2.close()
                   return ('已退出')
       return ('用户{}登陆成功'.format(name2))
   def judgment1(self): #判断输入的用户名和密码是否在user文件中，在的话登陆成功，不在的话注册后跳转到judgment2(self):，重新登陆也跳转到judgment2(self):
      f1 = open('users','r+',encoding='utf-8')
      x1= eval(f1.read())
      name = self.id
      password = self.mima
      if (name,password) not in x1.items():
           print('用户名或密码错误')
           choice = int(input('注册请输入1，重新登陆请输入2,退出请输入3:   '))
           if choice == 1:
               name1 = input('用户名:   ')
               password1 = input('密码:    ')
               repassword1 = input('再次输入密码:   ')
               if name1 in x1.keys():
                    print('用户名重复，请重新输入')
               else:
                      if  not password1 or not name1 or not name1 and not password1:
                         print('用户名或密码不能为零')
                      elif password1 != repassword1:
                         print('两次输入密码不一致')
                      elif password1 == repassword1:
                         new_dic = {name1:password1}
                         x1.update(new_dic)
                         f1.seek(0)
                         f1.truncate()
                         f1.seek(0)
                         f1.write(str(x1))
                         print('用户{}注册成功'.format(name1))
                         f1.close()
                         return self.judgment2()
           elif choice == 2:
               return self.judgment2()
           elif choice == 3:
               return ('已退出')
      else:
           return ('用户{}登陆成功'.format(name))
denglu = login(input('用户名:    '),input('密码:    '))
print(denglu.judgment1())
5.用生成器实现斐波那契数列

def func(num):
 a = 0
 b = 1
 for i in range(num):
    c = a
    a = b
    b = c + b
    yield c
res = func(10)
print(next(res))
print(next(res))
print(next(res))
print(next(res))
print(next(res))
print(next(res))
print(next(res))
print(next(res))
print(next(res))
print(next(res))
以上均为我自己写出来的，可能有问题，欢迎大家指点