hobbsCalc.py 文件源码

def bft(tree):
    """ Perform a breadth-first traversal of a tree.
    Return the nodes in a list in level-order.

    Args:
        tree: a tree node
    Returns:
        lst: a list of tree nodes in left-to-right level-order
    """
    lst = []
    queue = Queue.Queue()
    queue.put(tree)
    while not queue.empty():
        node = queue.get()
        lst.append(node)
        for child in node:
            if isinstance(child, nltk.Tree):
                queue.put(child)
    return lst