Question

Imagine the following class that displays some sort of hierarchy:

class BaseList2D(object):
    def __init__(self):
        self._superobject   = None
        self._subobjects    = []

    def InsertUnder(self, other):
        if self not in other._subobjects:
            other._subobjects.append(self)
            self._superobject   = other
            return True
        return False

    def InsertAfter(self, other):
        parent  = other._superobject
        if not parent:
            return False

        parent  = parent._subobjects
        parent.insert(parent.index(other) + 1, self)
        return True

    def GetDown(self):
        if not len(self._subobjects):
            return
        return self._subobjects[0]

    def GetNext(self):
        if not self._superobject:
            return
        stree   = self._superobject._subobjects
        index   = stree.index(self)
        if index + 1 >= len(stree):
            return
        return stree[index + 1]

Is it really the best (or the only) way to set the superobject of other by accessing it’s hidden attribute ? The attribute should not be set by the user ..

Answer 1

_foo is just a naming convention. Usually, there would be a property or something that sets the ‘private’ variable for you. If not, the convention is being (slightly) misused.