从python中获取容器/父对象 [英] Getting container/parent object from within python

问题描述

在Python中，是否可以从Bar内部获取包含另一个对象Bar的对象，Foo？这里是我的意思的例子

In Python, is it possible to get the object, say Foo, that contains another object, Bar, from within Bar itself? Here is an example of what I mean

class Foo(object):
    def __init__(self):
        self.bar = Bar()
        self.text = "Hello World"

class Bar(object):
    def __init__(self):
        self.newText = foo.text #This is what I want to do, 
                                #access the properties of the container object

foo = Foo()

这可能吗？感谢！

推荐答案

将引用传递给Bar对象，如下所示：

Pass a reference to the Bar object, like so:

class Foo(object):
    def __init__(self):
        self.text = "Hello World"  # has to be created first, so Bar.__init__ can reference it
        self.bar = Bar(self)

class Bar(object):
    def __init__(self, parent):
        self.parent = parent
        self.newText = parent.text

foo = Foo()

$ b b

编辑：@thomleo指出，这可能会导致垃圾回收问题。建议的解决方案在 http://eli.thegreenplace.net/ 2009/06/12 / safely-using-destructors-in-python / ，看起来像

as pointed out by @thomleo, this can cause problems with garbage collection. The suggested solution is laid out at http://eli.thegreenplace.net/2009/06/12/safely-using-destructors-in-python/ and looks like

import weakref

class Foo(object):
    def __init__(self):
        self.text = "Hello World"
        self.bar = Bar(self)

class Bar(object):
    def __init__(self, parent):
        self.parent = weakref.ref(parent)    # <= garbage-collector safe!
        self.newText = parent.text

foo = Foo()

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