As mentioned earlier, A Python decorator is a function that takes in a function and returns it by adding some functionality. In fact, any object which implements the special__call__()method is termed callable. So, in the most basic sense, a decorator is a callable that returns a callable...
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 = ...
Let’s modify the above example to see what happens when we add arguments to the decorator: 代码语言:javascript 代码运行次数:0 运行 AI代码解释 # PythonDecorators/decorator_with_arguments.pyclass decorator_with_arguments(object): def __init__(self, arg1, arg2, arg3): """ If there are dec...
This one allows you to pass arguments into the decorator for some additional customization. It needs to wrap everything in an additional function (creating a closure) in order to make this possible. fromfunctoolsimportwrapsdefmy_decorator(extra_value=None):def_my_decorator(view_func):def_decorato...
Example code importfunctoolsdefdecorator(func):@functools.wraps(func)defwrapper_decorator(*args, **kwargs):# Do something beforevalue = func(*args, **kwargs)# Do something afterreturnvaluereturnwrapper_decorator Timer Example Code importfunctoolsimporttimedeftimer(func):"""Print the runtime of the...
It retains access to the function being decorated and any additional state or arguments defined in the decorator function. For example: def simple_decorator(func): def wrapper(): print("Before the function call") func() print("After the function call") return wrapper @simple_decorator def ...
With that in mind, we can write a function that returns a wrapper function. 7.6.1. Nesting a Decorator Within a Function Let’s go back to our logging example, and create a wrapper which lets us specify a logfile to output to. from functools import wraps def logit(logfile='out.log')...
Simple exampleIn the next example, we create a simple decorator example. main.py #!/usr/bin/python def enclose(fun): def wrapper(): print("***") fun() print("***") return wrapper def myfun(): print("myfun") enc = enclose(myfun) enc() The enclose function is a decorator...
@wrapt.decorator def wrapper(wrapped, instance, args, kwargs): return wrapped(*args, **kwargs) return wrapper @with_arguments(1, 2) def function(): pass 使用wrapt的装饰器嵌套 import wrapt @wrapt.decorator def uppercase(wrapped, instance, args, kwargs): ...
defa_decorator_passing_arbitrary_arguments(function_to_decorate):# The wrapper accepts any argumentsdefa_wrapper_accepting_arbitrary_arguments(*args, **kwargs):print"Do I have args?:"printargsprintkwargs# Then you unpack the arguments, here *args, **kwargs# If you are not familiar with ...