Can hasattr go multiple children deep in Python?

If I have node.child1.child2, can I use hasattr(node, 'child1.child2') effectiv开发者_如何学编程ely? Will it error if there's no child1 or simply return false?

hasattr doesn't take a dotted name like that and navigate down attribute chains. But you can write a function to do it:

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

Here's one way of doing it:

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

Call it like this:

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