Question

我想使用递归在通用树中找到一个节点，但我似乎无法使其正常工作。我将其作为类中的方法进行了设置，并且仅发布了该方法。我正在使用python 3.任何帮助将不胜感激

def search_tree2(self, node):
    if self.name == node.name:
        return self
    elif self.child_nodes:
        result = None
        for child in self.child_nodes:
            if child.name == node.name:
                result = child
            elif child.child_nodes:
                result = child.search_tree2(child)
                if result.child_nodes:
                    for kid in result.child_nodes:
                        if kid.name == node.name:
                            result = kid
        return result
    else:
        return None

编辑：使用Neel Mehta的更新方法添加了其余代码。为清楚起见，我想做的就是通过搜索节点在树中的任何节点上向该树添加一个节点，然后添加新节点。我也在移动设备上，因此粘贴代码有点困难；这就是为什么我最初只发布代码段的原因。

class Tree:
    def __init__(self, value=None, name=None, parent=None):
        self.value = value
        self.name = name
        self.parent = parent
        self.child_nodes = []

    def add_node(self, value=None, name=None, parent=None):
        node = Tree(value, name, parent)
        if node.parent.name == 'root':
            self.child_nodes.append(node)
        else:
            parent_node = self.search_tree2(node.parent)
            if parent_node:
                parent_node.child_nodes.append(node)
                print(node.name, 'added..')
            else:
                print('Parent Node not found.')
        return node

    def print_tree(self, node):
        if node.name:
            if node.name == 'root':
                pass
            else:
                print(node.name.title() + ', ', 'age ', str(node.value) + ', ' if node.value else 'unknown' + ', ',
                      'with parent ', node.parent.name, ' and ',
                      *[node.child_nodes[i].name + ' ' for i in range(len(node.child_nodes))] if len(
                          node.child_nodes) > 0 else 'no one ', 'as children.', sep='')
            if node.child_nodes:
                for member in node.child_nodes:
                    member.print_tree(member)

    def search_tree2(self, node):
        if self.name == node.name:
            return self
        elif self.child_nodes:
            for child in self.child_nodes:
                result = child.search_tree2(node)
                if result:
                    return result
        return None

    def delete_node(self, node):
        parent = self.search_tree2(node.parent)
        for child in parent.child_nodes:
            if child.name == node.name:
                parent.child_nodes.remove(child)


family = Tree(name='root', parent=None)
rebecca = family.add_node(value=64, name='Rebecca', parent=family)
jack = family.add_node(value=64, name='Jack', parent=family)
kate = family.add_node(value=36, name='Kate', parent=jack)
randall = family.add_node(value=36, name='Randall', parent=jack)
kevin = family.add_node(value=36, name='Kevin', parent=rebecca)
becky = family.add_node(value=11, name='Becky', parent=kevin)
daisy = family.add_node(value=8, name='Daisy', parent=randall)
jen = family.add_node(value=22, name='Jen', parent=kate)
william = family.add_node(value=8, name='William', parent=daisy)
kyle = family.add_node(value=20, name='Kyle', parent=kate)

Answer 1

正如您在问题中提到的，您想使用递归。这意味着您应该从函数中调用要定义的函数。

当您遍历节点的子代时，可以在子代上调用search_tree2。这将确保它递归树的整个深度。它还将在所有节点上执行您定义的逻辑，因此您无需在循环中为子级添加if条件。

您的代码将如下所示：

def search_tree2(self, node):
    if self.name == node.name:
        return self
    elif self.child_nodes:
        for child in self.child_nodes:
            result = child.seach_tree2(node)
            if result:
                return result

    # Could not find the result in any of the children
    return None

在python中使用递归在通用树中查找节点

1 个答案: