Python练习--函数
一：编写函数，（函数执行的时间是随机的）
#!/usr/bin/evn python
# -*- coding:utf-8 -*-
# author:stealth
import time,random
def print_time():
time.sleep(random.randrange(0,3))
print(random.randrange(0,3))
print_time()
二：编写装饰器，为函数加上统计时间的功能
#!/usr/bin/evn python
# -*- coding:utf-8 -*-
# author:stealth
import time
def timmer(func):
def wrapper(*args,**kwargs):
start_time = time.time()
res = func(*args,**kwargs)
stop_time = time.time()
print('函数运行时间是：%s' %(stop_time-start_time))
return res
return wrapper
@timmer
def foo():
time.sleep(2)
print('这个是foo运行的结果')
foo()
三：编写装饰器，为函数加上认证的功能
#!/usr/bin/evn python
# -*- coding:utf-8 -*-
# author:stealth
def auth(dirver='file'):
def auth2(func):
def wrapper(*args,**kwargs):
name = input("user:")
pwd = input("pwd:")
if dirver == 'file':
if name == 'egon' and pwd == '123':
print('登录成功')
res = func(*args,**kwargs)
return res
else:
res = '用户名或密码错误！'
print(res)
elif dirver == 'ldap':
print('ldap')
return wrapper
return auth2
@auth(dirver='file')
def foo(name):
print(name)
foo('egon')四：编写装饰器，为多个函数加上认证的功能（用户的账号密码来源于文件），要求登录成功一次，后续的函数都无需再输入用户名和密码
注意：从文件中读出字符串形式的字典，可以用eval('{"name":"egon","password":"123"}')转成字典格式
#!/usr/bin/evn python
# -*- coding:utf-8 -*-
# author:stealth
db = 'db.txt'
login_status = {'user':None,'status':False}
def auth(auth_type='file'):
def auth2(func):
def warpper(*args,**kwargs):
if login_status['user'] and login_status['status']:
return func(*args,**kwargs)
if auth_type == 'file':
tag = True
while tag:
with open(db,'r',encoding='utf-8') as read_f:
dic = eval(read_f.read())
name = input('请输入用户名：').strip()
passwd = input('请输入密码：').strip()
if name in dic and passwd == dic[name]:
login_status['user'] = name
login_status['status'] = True
res = func(*args,**kwargs)
tag = False
return res
else:
print('您输入的用户名或密码错误！')
elif auth_type == 'mysql':
pass
return warpper
return auth2
def index():
print('欢迎来到首页')
@auth()
def home(name):
print('欢迎来到%s的首页' %name)
@auth()
def shopping(name):
print('欢迎来到%s的购物车' %name)
@auth()
def order(name):
print('欢迎来到%s的订单列表' %name)
index()
home('stealth')
shopping('stealth')
order('stealth')五：编写装饰器，为多个函数加上认证功能，要求登录成功一次，在超时时间内无需重复登录，超过了超时时间，则必须重新登录
#!/usr/bin/evn python
# -*- coding:utf-8 -*-
# author:stealth
import time,random
db = 'db.txt'
login_status = {'user':None,'status':False,'login_time':None,'timeout':2}
def timeer(func):
def wrapper(*args,**kwargs):
s1 = time.time()
res = func(*args,**kwargs)
s2 = time.time()
print('%s' %(s2-s1))
return res
return wrapper
def auth(auth_type='file'):
def auth2(func):
def warpper(*args,**kwargs):
if auth_type == 'file':
if login_status['user']:
timeout = time.time()-login_status['login_time']
if timeout < login_status['timeout']:
return func(*args, **kwargs)
tag = True
while tag:
with open(db,'r',encoding='utf-8') as read_f:
dic = eval(read_f.read())
name = input('请输入用户名：').strip()
passwd = input('请输入密码：').strip()
if name in dic and passwd == dic[name]:
login_status['user'] = name
login_status['status'] = True
login_status['login_time'] = time.time()
res = func(*args,**kwargs)
tag = False
return res
else:
print('您输入的用户名或密码错误！')
elif auth_type == 'mysql':
pass
return warpper
return auth2
@auth()
def index():
time.sleep(random.randrange(3))
print('欢迎来到首页')
@auth()
def home(name):
time.sleep(random.randrange(3))
print('欢迎来到%s的首页' %name)
@auth()
def shopping(name):
time.sleep(random.randrange(3))
print('欢迎来到%s的购物车' %name)
@auth()
def order(name):
time.sleep(random.randrange(3))
print('欢迎来到%s的订单列表' %name)
index()
home('stealth')
shopping('stealth')
order('stealth')六：编写下载网页内容的函数，要求功能是：用户传入一个url，函数返回下载页面的结果
from urllib.request import urlopen
def index(url):
def get():
return urlopen(url).read()
return get
baidu = index('http://www.baidu.com')
print(baidu().decode('utf-8'))七：为题目五编写装饰器，实现缓存网页内容的功能：
具体：实现下载的页面存放于文件中，如果文件内有值（文件大小不为0），就优先从文件中读取网页内容，否则，就去下载，然后存到文件中
扩展功能：用户可以选择缓存介质/缓存引擎，针对不同的url，缓存到不同的文件中
#!/usr/bin/evn python
# -*- coding:utf-8 -*-
# author:stealth
import hashlib,os,requests
engine_setting = {
'file':{'dirname':'c:\db'},
'mysql':{
'host':'127.0.0.1',
'port':3306,
'user':'root',
'password':'pass123',
'database':'web_cache'},
'redis':{
'host':'127.0.0.1',
'port':6379,
'user':'root',
'password':'pass123'}
}
def make_cache(engine='file'):
if engine not in engine_setting:
raise TypeError('egine not valid')
def deco(func):
def wrapper(url):
if engine == 'file':
m = hashlib.md5(url.encode('utf-8'))
cache_filename = m.hexdigest()
cache_filepath = r'%s/%s' %(engine_setting['file']['dirname'],cache_filename)
if os.path.exists(cache_filepath) and os.path.getsize(cache_filepath):
with open(cache_filepath,'r',encoding='utf-8') as read_f:
return read_f.read()
res = func(url)
with open(cache_filepath,'w',encoding='utf-8') as f:
f.write(res)
return res
elif engine == 'mysql':
pass
elif engine == 'redis':
pass
else:
pass
return wrapper
return deco
@make_cache(engine='file')
def get(url):
return requests.get(url).text
print(get('https://www.baidu.com'))
print(get('https://map.baidu.com'))
八：还记得我们用函数对象的概念，制作一个函数字典的操作吗，来来来，我们有更高大上的做法，在文件开头声明一个空字典，然后在每个函数前加上装饰器，完成自动添加到字典的操作
#!/usr/bin/evn python
# -*- coding:utf-8 -*-
# author:stealth
route_dic = {}
def make_route(name):
def deco(func):
route_dic[name] = func
return deco
@make_route('select')
def func1():
print('select')
@make_route('insert')
def func2():
print('insert')
@make_route('update')
def func3():
print('update')
@make_route('delete')
def func4():
print('delete')
@make_route('create')
def func5():
print('create')
print(route_dic)九 编写日志装饰器，实现功能如：一旦函数f1执行，则将消息2017-07-21 11:12:11 f1 run写入到日志文件中，日志文件路径可以指定
注意：时间格式的获取
import time
time.strftime('%Y-%m-%d %X')
#!/usr/bin/evn python
# -*- coding:utf-8 -*-
# author:stealth
import time,os
def logger(logfile):
def deco(func):
def wrapper(*args,**kwargs):
res = func(*args,**kwargs)
with open(logfile,'a+',encoding='utf-8') as f:
f.write('%s run\n' %(time.strftime('%Y-%m-%d %X')))
return res
return wrapper
return deco
@logger('log1.txt')
def index():
print('欢迎来到首页')
index()
time.sleep(3)
index()
time.sleep(3)
index()