example_function(1000000) 输出示例: example_function ran in: 0.12345 secs2.2 使用functools.wraps保持元信息 直接应用上述装饰器会丢失被装饰函数的一些重要属性,比如函数名、文档字符串等。为了解决这个问题,可以使用functools.wraps来保留这些元数据: from functools import wraps import time def timing_decorator_wi...
You’ll start with an example:Python hello_decorator.py def decorator(func): def wrapper(): print("Something is happening before the function is called.") func() print("Something is happening after the function is called.") return wrapper def say_whee(): print("Whee!") say_whee = ...
这个函数接收一个函数作为参数defmy_shiny_new_decorator(a_function_to_decorate):# Inside, the decorator defines a function on the fly: the wrapper.# This function is going to be wrapped around the original function# so it can execute code before and after it.# 在装饰器(decorator)内部定义...
在Python中,装饰器通常通过@decorator_name的形式来使用,这是一种语法糖,实际上是对函数进行如下调用的简写: def decorated_function(): ... decorated_function = decorator(decorated_function)2.2.3 基础装饰器实例演示 下面是一个日志装饰器的基础实现,它会在函数执行前后打印相关信息: import time def log_deco...
In the example shown above,make_pretty()is a decorator. Notice the code, decorated_func = make_pretty(ordinary) We are now passing theordinary()function as the argument to themake_pretty(). Themake_pretty()function returns the inner function, and it is now assigned to thedecorated_funcvari...
Instead, Python allows you to use decorators in a simpler way with the@symbol, sometimes called the“pie” syntax. The following example does the exact same thing as the first decorator example: defmy_decorator(func):defwrapper():print("Something is happening before the function is called.")...
A class decorator: fromfunctoolsimportwrapsclassmy_decorator(object):def__init__(self,view_func):self.view_func=view_funcwraps(view_func)(self)def__call__(self,request,*args,**kwargs):# maybe do something before the view_func callresponse=self.view_func(request,*args,**kwargs)# maybe ...
The @property Decorator In Python,property()is a built-in function that creates and returns apropertyobject. The syntax of thisfunctionis: property(fget=None, fset=None, fdel=None, doc=None) Here, fgetis function to get value of the attribute ...
For example: def simple_decorator(func): def wrapper(): print("Before the function call") func() print("After the function call") return wrapper @simple_decorator def greet(): print("Hello!") greet() # Output: # Before the function call # Hello! # After the function call Powered By...
这里介绍python的装饰器(decorator)。 个人理解,装饰器就是给函数套一个壳,在执行函数前或者执行函数后做点其它的操作,比如记录函数运算时间。 下面会介绍几个用了装饰器的例子,通过弄明白这些例子,对装饰器的用法会有更广的认识,而不只是用来计时。 本文的代码链接: ...