一、装饰器
- 装饰器本质是函数
- 为其他函数添加附加功能
- 不修改被修饰函数的源代码
- 不修改被修饰函数的调用方式
- 装饰器示例
import time
def timmer(func):
def wrapper(*args,**kwargs):
start_time = time.time()
res = func(*args,**kwargs)
stop_time = time.time()
print("函数的运行时间:%s" % (stop_time - start_time))
return res
return wrapper
@timmer
def calc(l):
s = 0
for i in l:
s += i
time.sleep(0.1)
return s
print(calc(range(20)))
- 装饰器示例2
import time
def timmer(func):
def wrapper():
start_time = time.time()
func() #运行传进来的f函数
stop_time = time.time()
print("函数的运行时间是: %s" % (stop_time - start_time))
return wrapper
@timmer #f = timmer(f) #将f函数传给timmer
def f():
time.sleep(3)
print("f 函数运行完成。")
f() #执行wrapper()
- 修饰带返回值的函数
import time
def timmer(func):
def wrapper():
start_time = time.time()
res = func() #运行传进来的f函数
stop_time = time.time()
print("函数的运行时间是: %s" % (stop_time - start_time))
return res #将f函数的返回值返回
return wrapper
@timmer #f = timmer(f) #将f函数传给timmer
def f():
time.sleep(3)
print("f 函数运行完成。")
return "f函数的返回值"
- 修饰带参数的函数
import time
def timmer(func):
def wrapper(*args,**kwargs):
start_time = time.time()
res = func(*args,**kwargs) #运行传进来的f函数
stop_time = time.time()
print("函数的运行时间是: %s" % (stop_time - start_time))
return res #将f函数的返回值返回
return wrapper
@timmer #f = timmer(f) #将f函数传给timmer
def f(name):
time.sleep(1)
print("f 函数运行完成。函数的参数是:%s" %name)
return "f函数的返回值"
res = f("dongfei") #执行wrapper()
print(res)
- 认证登录装饰器示例
def auth(func):
def warpper(*args,**kwargs):
username = input("your username: ")
password = input("your password: ")
if username == "dongfei" and password == "123":
res = func(*args,**kwargs)
return res
else:
print("username or password error!")
return warpper
def index():
print("welcome to my index page.")
@auth
def home(name):
print("%s go home" %name)
@auth
def shopping_car():
print("your shopping_car")
index()
home("dongfei")
shopping_car()
- 模拟记录session
user_list = [
{"username":"dongfei", "password":"123456"},
{"username":"dongfei2", "password":"123456"},
{"username":"dongfei3", "password":"123456"},
{"username":"dongfei4", "password":"123456"},
]
current_dic = {"username":None, "login_status":False}
def auth(func):
def warpper(*args,**kwargs):
if current_dic["username"] and current_dic["login_status"]:
res = func(*args, **kwargs)
return res
username = input("your username: ")
password = input("your password: ")
for user_dic in user_list:
if username == user_dic["username"] and password == user_dic["password"]:
current_dic["username"] = username
current_dic["login_status"] = True
res = func(*args,**kwargs)
return res
else:
print("username or password error!")
return warpper
def index():
print("welcome to my index page.")
@auth
def home(name):
print("%s go home" %name)
@auth
def shopping_car():
print("your shopping_car")
index()
home("dongfei")
shopping_car()
- 带参数的装饰器
user_list = [
{"username":"dongfei", "password":"123456"},
{"username":"dongfei2", "password":"123456"},
{"username":"dongfei3", "password":"123456"},
{"username":"dongfei4", "password":"123456"},
]
current_dic = {"username":None, "login_status":False}
def auth(auth_type):
def auth_func(func):
def warpper(*args,**kwargs):
if auth_type == "file_db":
if current_dic["username"] and current_dic["login_status"]:
res = func(*args, **kwargs)
return res
username = input("your username: ")
password = input("your password: ")
for user_dic in user_list:
if username == user_dic["username"] and password == user_dic["password"]:
current_dic["username"] = username
current_dic["login_status"] = True
res = func(*args,**kwargs)
return res
else:
print("username or password error!")
elif auth_type == "mysql_db":
print("请使用%s认证:" %auth_type)
else:
print("无效的认证类型")
return warpper
return auth_func
@auth("ldap")
def index():
print("welcome to my index page.")
@auth(auth_type="mysql_db") # @auth(auth_type="mysql") 等于 @auth_func
def home(name):
print("%s go home" %name)
@auth(auth_type="file_db")
def shopping_car():
print("your shopping_car")
index()
home("dongfei")
shopping_car()
二、高阶函数
- 函数接受的参数是一个函数名
- 函数的返回值是一个函数名
- 满足以上条件的任意一个都是高阶函数
import time
def foo():
print("from foo")
time.sleep(2)
def timmer(func):
start_time = time.time()
func()
stop_time = time.time()
print("函数的运行时间:%s" % (stop_time - start_time))
return func
foo = timmer(foo)
foo()
三、解压序列
>>> a,*_,c = [1,2,3,4,5,6,7,8] #取第一个和最后一个值
>>> a
1
>>> c
8
>>> _
[2, 3, 4, 5, 6, 7]
原文地址:https://www.cnblogs.com/L-dongf/p/10657651.html
时间: 2024-10-07 15:45:55