修改其类的数据对象的函数

Question

我想定义一个函数，将其称为test_controller()，并且我想将此函数传递给构造函数：my_thing = TestClass(test_controller)。该功能需要能够修改其类的数据对象。我听说过Python 3的nonlocal关键字，但我正在运行Python 2.7。可能吗？我该怎么做呢？这是我已经尝试过的。

class TestClass(object): 

    def __init__(self, ctrl_func): 
     self.a = 4 
     self.ctrl_func = ctrl_func 

    def do_stuff(self): 
     self.ctrl_func() 

def test_controller(): 
    global a 
    a = 20 

my_thing = TestClass(test_controller) 
print my_thing.a   #this prints 4 
my_thing.ctrl_func() 
print my_thing.a   #this prints 4 but I want it to print 20 

Answer 1

您可以传递任何您想要修改的对象的引用。

class TestClass(object): 

    def __init__(self, ctrl_func): 
     self.a = 4 
     self.ctrl_func = ctrl_func 

    def do_stuff(self): 
     self.ctrl_func(self) 

def test_controller(self): 
    self.a = 20 

my_thing = TestClass(test_controller) 
print my_thing.a   #this prints 4 
my_thing.ctrl_func(my_thing) 
print my_thing.a   #this prints 4 but I want it to print 20 

或者，您可以ctrl_func转换为对象的绑定方法：

import types 

class TestClass(object): 

    def __init__(self, ctrl_func): 
     self.a = 4 
     self.ctrl_func = types.MethodType(ctrl_func, self) 

    def do_stuff(self): 
     self.ctrl_func() 

def test_controller(self): 
    self.a = 20 

my_thing = TestClass(test_controller) 
print my_thing.a   #this prints 4 
my_thing.ctrl_func() 
print my_thing.a   #this prints 4 but I want it to print 20 

参考：

• https://stackoverflow.com/a/1015405/8747
• http://igorsobreira.com/2011/02/06/adding-methods-dynamically-in-python.html