013装饰器（重点）

Posted 2020-10-19 Alos

##闭包 ：内部函数，在外部调用不在他函数范围的变量

def  outer():
    x=10
    def  inner():
        print(x)
    return   inner
#outer()()
f=outer()

f()

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 这里inner就是一个闭包，闭包=内部函数+环境，这里环境是x=10。
闭包是为了解释调用不在他范围的变量的现象

##装饰器

 1 import  time
 2 def  show_runtime(func):
 3     def  inner():
 4         start_time=time.time()
 5         time.sleep(1)
 6         func()
 7         end_time=time.time()
 8         print(end_time-start_time)
 9     return  inner
10 
11 def  f():
12     print(\'aiq\')
13 
14 f=show_runtime(f)         #装饰f函数
15 f()

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show_runtime()方法就是一个装饰器
高大上的用法：

@show_runtime  # 等于f=show_runtime(f)，这样已经装饰了
def  f():
    print(\'aiq\')

#装饰器里面的参数，在inner函数加参数，以及inner里面的函数也要加参数

import  time
def  show_runtime(func):
    def  inner(*x,**y):
        start_time=time.time()
        func(*x,**y)
        end_time=time.time()
        print(end_time-start_time)
    return  inner

@show_runtime               #等于f=show_runtime(f)
def  add(*a,**b):
    sum=0
    for  i  in  a:
        sum+=i
    print(sum)
    time.sleep(1)
add(3,5,7)

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import  time
def  logger(flag=False):
    def  show_runtime(func):
        def  inner(*x,**y):
            start_time=time.time()
            func(*x,**y)
            end_time=time.time()
            print(end_time-start_time)
            if  flag==True:                #如果标记是True则执行
                pass
        return  inner
    return  show_runtime

@logger(True)    #等于先调用logger函数，然后在执行@show_time,这里相当于闭包，调用外部的变量
def  add(*a,**b):
    sum=0
    for  i  in  a:
        sum+=i
    print(sum)
    time.sleep(1)
add(3,5,7)

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作业：

 1 # __author: _nbloser
 2 # date: 2017/12/25
 3 # username, passwd = \'xia\', 123  # 要在文件里面的
 4 def read_user_messege(file_name):
 5     f = open(file_name)
 6     data = eval(f.read())
 7     f.close()
 8     return data
 9 
10 
11 def logger(auth_type=\'jingdong\'):
12     def decorator(func):
13         def inner():
14             global status_login
15             if status_login == False:
16                 username_input = input(\'input username:\')
17                 user_table = read_user_messege(\'\'.join([auth_type, \'.txt\']))
18                 if username_input in user_table:
19                     passwd_input = input(\'input passwd:\')
20                     if user_table[username_input] == passwd_input:
21                         status_login = True
22                         func()
23                     else:
24                         print(\'密码错误，登录失败!\')
25                 else:
26                     print(\'没有该用户\')
27             if status_login == True:
28                 func()
29 
30         return inner
31 
32     return decorator
33 
34 
35 @logger()
36 def home():
37     print("welcome,  home page.")
38 
39 
40 @logger(\'wechat\')
41 def finance():
42     print(\'finance.\')
43 
44 
45 @logger()
46 def book():
47     print(\'book\')
48 
49 
50 status_login = False
51 while True:
52     print(\'1:home\\n\'
53           \'2:finance\\n\'
54           \'3:book\\n\'
55           \'others:exit\\n\')
56     elect = input(\'>>>\')
57     if elect == \'1\':
58         home()
59     elif elect == \'2\':
60         finance()
61     elif elect == \'3\':
62         book()
63     else:
64         break

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jingdong.txt： {\'xia\': \'aiq\', \'q\': \'aix\'}

wechat.txt：{\'xia\': \'wh_aiq\', \'q\': \'wh_aix\'}

 

补充书中例子：因为这个没有基础，个人觉得多写几个熟悉。

 1 # __author: _nbloser
 2 # date: 2017/12/25
 3 
 4 def foo(f):
 5     """foo function Docstring"""
 6 
 7     def wrapper(*x, **y):
 8         """wrapper  doc"""
 9         print(\'调用函数：\', f.__name__)
10         return f(*x, **y)
11 
12     return wrapper
13 
14 @foo
15 def bar(x):
16     return x**2
17 
18 if __name__==\'__main__\':
19     print(bar(2))
20     print(bar.__name__)
21     print(bar.__doc__)

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 1 # __author: _nbloser
 2 # date: 2017/12/25
 3 
 4 def outter(func):
 5     def inner(*x, **y):
 6         print(\'aiq\')
 7         func(*x, **y)
 8 
 9     return inner
10 
11 
12 @outter
13 def my_add(a, b):
14     print(a + b)
15 
16 
17 if __name__ == \'__main__\':
18     my_add(2, 8)

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 1 # __author: _nbloser
 2 # date: 2017/12/25
 3 
 4 import time, functools
 5 
 6 
 7 def timeit(func):
 8     def wrapper(*args):
 9         start = time.perf_counter()
10         func(*args)
11         end = time.perf_counter()
12         print(\'运行时间：\', end - start)
13 
14     return wrapper
15 
16 
17 @timeit
18 def my_sum(n):
19     sum = 0
20     for i in range(n):
21         sum += i
22     print(sum)
23 
24 
25 if __name__ == \'__main__\':
26     my_sum(10000)

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 1 # __author: _nbloser
 2 # date: 2017/12/25
 3 
 4 import time
 5 
 6 
 7 def outer(func):
 8     def inner(*args):
 9         start_time = time.time()
10         func(*args)
11         time.sleep(1)
12         end_time = time.time()
13         print(\'运行时间：\', end_time - start_time)
14 
15     return inner
16 
17 
18 @outer
19 def my_factorial(n):
20     product = 1
21     for i in range(2, n):
22         product *= i
23     print(product)
24 
25 
26 my_factorial(25)

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 1 # __author: _nbloser
 2 # date: 2017/12/25
 3 def make_bold(func):
 4     def wrapper(*args):
 5         return \'\'.join([\'<b>\', func(*args), \'<b/>\'])
 6 
 7     return wrapper
 8 
 9 
10 def make_italic(func):
11     def wrapper(*args):
12         return \'\'.join([\'<i>\', func(*args), \'</i>\'])
13 
14     return wrapper
15 
16 
17 @make_bold
18 @make_italic
19 def html_tags(str1):
20     return str1
21 
22 
23 print(html_tags(\'hello\'))
24 # 运行结果：<b><i>hello</i><b/>

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