python装饰器模式带参数_python函数装饰器 类装饰器和带参数的装饰器——装饰器模式...

装饰器模式：

动态地给对象添加一些额外的职责，就增加功能来说，装饰模式比生产子类更加灵活

Component 是定义一个对象接口，可以给这些对象动态地添加职责。concreteComponent是定义一个具体对象，也可以给这个对象添加一些职责。decorator，装饰抽象类，继承

l component，从外类来扩展component类的功能，但对于component来说，是无需知道decorator存在的，至于concretedecorator就是具体的装饰对象，起到给component添加职责的功能

python 函数装饰器

import time

def dumpy_decorator(f):

def wrap_f(*args):

print("*" * 44)

print('Function to be decorated:', f.__name__)

print('nested wrapping function: ', wrap_f.__name__)

print("*" * 44)

print("ProfilingDecorator called")

start_time = time.time()

resutl = f(*args)

end_time = time.time()

print(f"""{end_time-start_time} elapsed""")

print("ProfilingDecorator called over")

return resutl

print('s')

# wrap_f.__name__=f.__name__

# wrap_f.__doc__=wrap_f.__doc__

return wrap_f

@dumpy_decorator

def fib(n):

print('inside fib')

if n < 2:

return

fibprev = 1

fib = 1

for num in range(2, n):

fibprev, fib = fib, fibprev + fib

return fib

if __name__ == '__main__':

print('wrapped function:', fib.__name__)

res = fib(77)

print(res)

结果

此函数装饰器导致函数的元信息改变

python标准库包含了一个模块，它允许保留__doc__和__name__的值不被改变

修改：

import time

from functools import wraps

def dumpy_decorator(f):

@wraps(f)

def wrap_f(*args):

print("*" * 44)

print('Function to be decorated:', f.__name__)

print('nested wrapping function: ', wrap_f.__name__)

print("*" * 44)

print("ProfilingDecorator called")

start_time = time.time()

结果：

python 类装饰器

import time

class ProfilingDecorator():

def __init__(self, f):

print('ProfilingDecorator initiated')

self.f = f

def __call__(self, *args, **kwargs):

print("ProfilingDecorator called")

start_time = time.time()

resutl = self.f(*args)

end_time = time.time()

print(f"""{end_time-start_time} elapsed""")

print("ProfilingDecorator called over")

return resutl

class ToHTMLDecorator():

def __init__(self,f):

print('html decorated inited')

self.f=f

def __call__(self, *args, **kwargs):

print('html decorated called')

res=self.f(*args)

print('html decorated over')

return "{}".format(res)

@ToHTMLDecorator

@ProfilingDecorator

def fib(n):

print('inside fib')

if n < 2:

return

fibprev = 1

fib = 1

for num in range(2, n):

fibprev, fib = fib, fibprev + fib

return fib

if __name__ == '__main__':

n = 77

res = fib(n)

print(f'''the result is {res}''')

结果：

带参数的装饰器

from functools import wraps

import time

def profiling_decorator_with_unit(unit):

def profile_decorator(f):

@wraps(f)

def wrap_f(*args):

start_time = time.time()

resutl = f(*args)

end_time = time.time()

if unit == 'seconds':

print(f"""{(end_time - start_time)/1000} elapsed""")

else:

print(f"""{(end_time - start_time) } elapsed""")

return resutl

return wrap_f

return profile_decorator

@profiling_decorator_with_unit('else')

def fib(n):

print('inside fib')

if n < 2:

return

fibprev = 1

fib = 1

for num in range(2, n):

fibprev, fib = fib, fibprev + fib

return fib

if __name__ == '__main__':

res = fib(77)

print(res)