[英]Can a method be a decorator of another method of the same class?
I have a class with a dull repeating pattern on their functions and I wanted to turn this pattern into a decorator. 我有一个类在他们的函数上有一个沉闷的重复模式,我想把这个模式变成一个装饰器。 But the thing is that this decorator must access some attributes of the current instance, so I wanted to turn it into a method in this class. 但问题是这个装饰器必须访问当前实例的一些属性,所以我想把它变成这个类中的方法。 I'm having some problems with that. 我遇到了一些问题。
So, this is similar to what I want: 所以,这与我想要的类似:
class DullRepetitiveClass:
def __init__(self, nicevariable):
self.nicevariable = nicevariable
def mydecorator(self, myfunction):
def call(*args, **kwargs):
print "Hi! The value of nicevariable is %s"%(self.nicevariable,)
return myfunction(*args, **kwargs)
return call
@mydecorator #Here, comment (1) below.
def somemethod(self, x):
return x + 1
(1) Here is the problem. (1)这是问题所在。 I want to use the DullRepetitiveClass.mydecorator
method to decorate the somemethod
method. 我想使用DullRepetitiveClass.mydecorator
方法来修饰somemethod
方法。 But I have no idea how to use the method from the current instance as the decorator. 但我不知道如何使用当前实例中的方法作为装饰器。
Is there a simple way of doing this? 有一个简单的方法吗?
EDIT: Ok, the answer is quite obvious. 编辑:好的,答案很明显。 As Sven puts it below, the decorator itself just transform the method. 正如Sven所说,装饰器本身只是改变了方法。 The method itself should deal with all things concerning the instance: 该方法本身应该处理与实例有关的所有事情:
def mydecorator(method):
def call(self, *args, **kwargs):
print "Hi! The value of nicevariable is %s"%(self.nicevariable,)
return method(self, *args, **kwargs)
return call
class DullRepetitiveClass:
def __init__(self, nicevariable):
self.nicevariable = nicevariable
@mydecorator
def somemethod(self, x):
return x + 1
The decorator gets only one parameter – the function or method it decorates. 装饰器只获得一个参数 - 它装饰的函数或方法。 It does not get passed an instance as self
parameter – at the moment the decorator is called, not even the class has been created, let alone an instance of the class. 它不会作为self
参数传递一个实例 - 在调用decorator时,甚至没有创建类,更不用说类的实例了。 The instance will be passed as first argument to the decorated function, so you should include self
as first parameter in the parameter list of call()
. 该实例将作为第一个参数传递给装饰函数,因此您应该将self
作为第一个参数包含在call()
的参数列表中。
I don't see the necessity to include the decorator in the class scope. 我没有看到在类范围中包含装饰器的必要性。 You can do this, but you can just as well have it at module scope. 您可以这样做,但您也可以在模块范围内使用它。
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