python基础（三）装饰器

字典推导式：

data_list = ['1 hello','2 world']

result = {item.split(" ")[0]: item.split(" ")[1] for item in data_list }

print(result)

data = 'wd=搜狗&rsv_spt=1&rsv_iqid=0xd787ab5d00049167&issp=1&f=8&rsv_bp=1&rsv_idx=2&ie=utf-8&tn=baiduhome_pg&rsv_enter=1&rsv_dl=tb&rsv_sug3=7&rsv_sug1=6&rsv_sug7=101&rsv_sug2=0&rsv_btype=i&inputT=1988&rsv_sug4=2956'

res_list=data.split("&")

res_dic = {item.split('=')[0]:item.split("=")[1] for item in data.split("&")}

print(res_dic)

'''

字典转化为string

'''

params = {'wd': '搜狗', 'rsv_spt': '1', 'rsv_iqid': '0xd787ab5d00049167', 'issp': '1', 'f': '8', 'rsv_bp': '1', 'rsv_idx': '2', 'ie': 'utf-8',

       'tn': 'baiduhome_pg', 'rsv_enter': '1', 'rsv_dl': 'tb', 'rsv_sug3': '7',

       'rsv_sug1': '6', 'rsv_sug7': '101', 'rsv_sug2': '0', 'rsv_btype': 'i',

       'inputT': '1988', 'rsv_sug4': '2956'}

li = []

for key,value in params.items():

   # str=key+"="+value  #相加效率低

   str = "{}={}".format(key,value)

   li.append(str)

res = "&".join(li)

print(res)

res = "&".join(["{}={}".format(key,value) for key,value in params.items()])

#集合推导式

data = {i for i in range(10)}

print(data)

闭包：函数嵌套函数，掉用外面函数不想立即执行内容，在该函数内嵌套函数，让内部函数工作，可以在内部封装自己想要的东西

def outer(name):

    def inner():

        msg = "{}".format(name)

        print(msg)

    return inner

v = outer("Jack")

v2 = outer("Lily")

v()

v2()

线程池：

装饰器：在不改变函数的基础上想在函数执行前后定制功能

def outer(a1):

    def inner():

        a1()

    return inner

def x():

    print("xx")

res = outer(x)

res()

@outer

def plus(v1):

    return  v1

res = plus(1)

print(res)

def outer(func):

    def inner(*args,**kwargs):

        return func(*args,**kwargs)

    return inner

@outer

def plus(v1):

    return  v1

res = plus(1)

print(res)

"""计算一个函数的执行时间"""

import time

def coast(arg):

    def inner():

        start = time.time()

        res = arg()

        end = time.time()

        print(end - start)

        return res

    return inner

@coast

def func():

    data = 0

    for i in range(10000000000):

        data += i

    return data

func()

def repeat_func(arg):

    def inner():

        result = 0

        for i in range(5):

            res = arg()

            result += res

        return result

    return inner

@repeat_func

def f1():

    return 123

t = f1()

print(t)

def outer(args):

    def inner(a1,a2):

        return args(a1,a2)

    return inner

@outer

def plus(v1,v2):

    return  v1+v2

res = plus(1,3)

print(res)

def outer(args):

    def inner(a1):

        return args(a1)

    return inner

@outer

def plus(v1):

    return  v1

res = plus(1)

print(res)

def outer(func):

    def inner(*args,**kwargs):

        return func(*args,**kwargs)

    return inner

@outer

def plus(v1):

    return  v1

res = plus(1)

print(res)

"""

带参数的装饰器

"""

def tt(count):

    def outer(func):

        def inner(*args,**kwargs):

            r = 0

            for i in range(count):

                res = func(*args,**kwargs)

                r += res

            return r

        return inner

    return outer

@tt(5)

def f(x):

    return x

res = f(100)

print(res)

传统的装饰器是由两层嵌套，带参数的装饰器是三层。

巴特西

python基础（三）装饰器

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