013装饰器（重点）

##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()

 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

import  time
def  show_runtime(func):
    def  inner():
        start_time=time.time()
        time.sleep(1)
        func()
        end_time=time.time()
        print(end_time-start_time)
    return  inner

def  f():
    print('aiq')

f=show_runtime(f)         #装饰f函数
f()

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)

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)

作业：

# __author: _nbloser
# date: 2017/12/25
# username, passwd = 'xia', 123  # 要在文件里面的
def read_user_messege(file_name):
    f = open(file_name)
    data = eval(f.read())
    f.close()
    return data


def logger(auth_type='jingdong'):
    def decorator(func):
        def inner():
            global status_login
            if status_login == False:
                username_input = input('input username:')
                user_table = read_user_messege(''.join([auth_type, '.txt']))
                if username_input in user_table:
                    passwd_input = input('input passwd:')
                    if user_table[username_input] == passwd_input:
                        status_login = True
                        func()
                    else:
                        print('密码错误，登录失败!')
                else:
                    print('没有该用户')
            if status_login == True:
                func()

        return inner

    return decorator


@logger()
def home():
    print("welcome,  home page.")


@logger('wechat')
def finance():
    print('finance.')


@logger()
def book():
    print('book')


status_login = False
while True:
    print('1:home
'
          '2:finance
'
          '3:book
'
          'others:exit
')
    elect = input('>>>')
    if elect == '1':
        home()
    elif elect == '2':
        finance()
    elif elect == '3':
        book()
    else:
        break

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。

# __author: _nbloser
# date: 2017/12/25

def foo(f):
    """foo function Docstring"""

    def wrapper(*x, **y):
        """wrapper  doc"""
        print('调用函数：', f.__name__)
        return f(*x, **y)

    return wrapper

@foo
def bar(x):
    return x**2

if __name__=='__main__':
    print(bar(2))
    print(bar.__name__)
    print(bar.__doc__)

# __author: _nbloser
# date: 2017/12/25

def outter(func):
    def inner(*x, **y):
        print('aiq')
        func(*x, **y)

    return inner


@outter
def my_add(a, b):
    print(a + b)


if __name__ == '__main__':
    my_add(2, 8)

# __author: _nbloser
# date: 2017/12/25

import time, functools


def timeit(func):
    def wrapper(*args):
        start = time.perf_counter()
        func(*args)
        end = time.perf_counter()
        print('运行时间：', end - start)

    return wrapper


@timeit
def my_sum(n):
    sum = 0
    for i in range(n):
        sum += i
    print(sum)


if __name__ == '__main__':
    my_sum(10000)

# __author: _nbloser
# date: 2017/12/25

import time


def outer(func):
    def inner(*args):
        start_time = time.time()
        func(*args)
        time.sleep(1)
        end_time = time.time()
        print('运行时间：', end_time - start_time)

    return inner


@outer
def my_factorial(n):
    product = 1
    for i in range(2, n):
        product *= i
    print(product)


my_factorial(25)

# __author: _nbloser
# date: 2017/12/25
def make_bold(func):
    def wrapper(*args):
        return ''.join(['<b>', func(*args), '<b/>'])

    return wrapper


def make_italic(func):
    def wrapper(*args):
        return ''.join(['<i>', func(*args), '</i>'])

    return wrapper


@make_bold
@make_italic
def html_tags(str1):
    return str1


print(html_tags('hello'))
# 运行结果：<b><i>hello</i><b/>