l = [1, 3]
变成生成器
f1 = list(l.__iter__())
f2 = list(iter(l))
print(f1)
print(f2)
器 函数的意思
装饰 为其它函数添加附加功能
装饰器 本质：函数， 功能：为其它函数添加附加功能
原则
1、不修改被修饰函数的源代码
2、不修改被修饰函数的调用方式
import time
def timmer(func):
def wapper(*args, **kwargs):
start_time = time.time()
res = func(*args, **kwargs)
stop_time = time.time()
print('函数的执行时间是%s' % (stop_time - start_time))
return res
return wapper
@timmer
def cal(l):
res = 0
for i in l:
time.sleep(0.1)
res += i
return res
d = cal(range(20))
print(d)
装饰器的知识储备
装饰器 = 高阶函数 + 函数嵌套 + 闭包
高阶参数
1、函数接收的参数是一个函数名
2、函数的返回值是一个函数名
3、满足上述任一条件的 都可以称为高阶函数
import time
def foo():
print('你好')
def test(func):
print(func)
start_time = time.time()
func()
stop_time = time.time()
print(stop_time-start_time)
test(foo)
def foo():
print('你好')
def test(func):
return func
foo = test(foo)
foo()
不修改foo源代码
不修改foo调用方式
多运行了一次，不合理 满足不了装饰器
import time
def foo():
time.sleep(3)
print('你好')
def timer(func):
start_time = time.time()
func()
stop_time = time.time()
print(stop_time-start_time)
return func
foo = timer(foo)
foo()
函数嵌套
def foo():
print('from foo')
def test():
pass
def father(name):
print('from father %s' %name)
def son():
print('from son' %name)
def grandson():
print('from grandson' %name)
grandson()
son()
print(locals())
father('林海峰')
闭包 封装变量 包裹
装饰器框架
import time
def timmer(func):
def wapper():
start_time = time.time()
func() #运行test
stop_time = time.time()
print(stop_time-start_time)
return wapper
@timmer
def test():
time.sleep(3)
print('test 函数运行完毕')
test = timmer(test) # 得到wapper 地址
test() # 执行wapper
语法糖 @timmer 就相当于 test = timmer(test)
函数闭包加上返回值
import time
def timmer(func):
def wapper():
start_time = time.time()
res = func() #运行test
stop_time = time.time()
print(stop_time-start_time)
return res
return wapper
@timmer
def test():
time.sleep(3)
print('test 函数运行完毕')
return '返回值'
print(test())
函数闭包加上返回值
import time
def timmer(func):
def wapper(*args, **kwargs):
start_time = time.time()
res = func(*args, **kwargs) # 运行test
stop_time = time.time()
print(stop_time - start_time)
return res
return wapper
@timmer
def test(name, age):
time.sleep(3)
print('名字%s' %name)
return '返回值'
@timmer
def test1(gender):
time.sleep(3)
print('性别%s' %gender)
return '返回值'
print(test('sss', 22))
print(test1('male'))
解压序列
a, b, c = (1, 2, 3)
print(a)
print(b)
print(c)
l = (1, 2, 3, 4, 5, 6, 7, 8, 9, 10)
a,*b,c = l
print(a)
print(b)
print(c)
f1 f2 值对换
f1 = 1
f2 = 2
f1, f2 = f2, f1
print(f1)
print(f2)
函数闭包加上认证功能
def auth_func(func):
def wapper(*args, **kwargs):
username = input('用户名：').strip()
password = input('密码：').strip()
if username == 'sb' and password=='123':
res = func(*args, **kwargs)
else:
print('错误')
return res
return wapper
@auth_func
def index():
print('欢迎来到主页')
@auth_func
def home(name):
print('欢迎回家%s' % name)
@auth_func
def shopping_car(name):
print('%s购物车' % name)
index()
home('ki')
shopping_car('ki')
函数闭包模拟session
user_list = [
{'name': 'alex', 'password': '123'},
{'name': 'peqi', 'password': '123'},
{'name': 'yuan', 'password': '123'},
{'name': 'keng', 'password': '123'}
]
current_dic = {'username': None, 'login': False}
def auth_func(func):
def wapper(*args, **kwargs):
if current_dic['username'] and current_dic['login']:
res = func(*args, **kwargs)
return res
username = input('用户名：').strip()
password = input('密码：').strip()
for user_dic in user_list:
if username == user_dic['name'] and password==user_dic['password']:
current_dic['username'] = username
current_dic['login'] = True
res = func(*args, **kwargs)
return res
else:
print('错误')
return wapper
@auth_func
def index():
print('欢迎来到主页')
@auth_func
def home(name):
print('欢迎回家%s' % name)
@auth_func
def shopping_car(name):
print('%s购物车' % name)
print('before---')
index()
home('小碗')
shopping_car('小碗')
函数闭包带参数的装饰器
user_list = [
{'name': 'alex', 'password': '123'},
{'name': 'peqi', 'password': '123'},
{'name': 'yuan', 'password': '123'},
{'name': 'keng', 'password': '123'}
]
current_dic = {'username': None, 'login': False}
def auth(auth_type='filedb'):
def auth_func(func):
def wapper(*args, **kwargs):
print(auth_type)
if auth_type== 'filedb':
if current_dic['username'] and current_dic['login']:
res = func(*args, **kwargs)
return res
username = input('用户名：').strip()
password = input('密码：').strip()
for user_dic in user_list:
if username == user_dic['name'] and password==user_dic['password']:
current_dic['username'] = username
current_dic['login'] = True
res = func(*args, **kwargs)
return res
else:
print('错误')
else:
print('其他方式解析')
return wapper
return auth_func
@auth(auth_type='filedb') # auth_func = auth(auth_type='filedb')-->@auth_funs 附加了一个auth_type
def index():
print('欢迎来到主页')
@auth(auth_type='filedb')
def home(name):
print('欢迎回家%s' % name)
@auth(auth_type='filedb')
def shopping_car(name):
print('%s购物车' % name)
print('before---')
index()
home('小碗')
shopping_car('小碗')
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