可以在Python中深入研究多个孩子吗？

Question

如果我有node.child1.child2,我可以asattr(node, 'child1.child2')有效地使用h 吗？如果没有child1或只是返回false,它会出错吗？

Answer 1

hasattr不会采用这样的虚线名称并向下导航属性链.但你可以写一个函数来做到这一点:

def get_deep_attr(obj, attrs):
    for attr in attrs.split("."):
        obj = getattr(obj, attr)
    return obj

def has_deep_attr(obj, attrs):
    try:
        get_deep_attr(obj, attrs)
        return True
    except AttributeError:
        return False

Answer 2

这是一种方法：

def hasattrdeep(obj, *names):
    for name in names:
       if not hasattr(obj, name):
            return False
       obj = getattr(obj, name)
    return True

像这样称呼它：

hasattrdeep(node) is True  # A side-effect. Could be made invalid if really desired by raising TypeError if len(names) == 0
hasattrdeep(node, 'foo') is False
hasattrdeep(node, 'child1') is True
hasattrdeep(node, 'child1', 'foo') is False
hasattrdeep(node, 'child1', 'child2') is True