Question

我需要从类节点中随机选择2个实例：

类节点：

def __init__(self, parent = None, length_to_parent = None, name = None, left = None, right = None, internal = 1, root = 0):
    self.parent = parent # parent node
    self.length_to_parent = length_to_parent # length to the parent node
    self.name = name # name of the node (to-be-defined name if external node(leaf), None if internal node)
    self.left = left # left child
    self.right = right # right child
    self.internal = internal # indicate if the node is an internal node
    self.root = root

我正在考虑将所有实例从节点存储到列表中，然后使用random.choose或random.shuffle从列表中随机选择2个节点。

但我不知道如何将实例存储到列表中......任何人都应该帮助！感谢

Answer 1

您可以像在其他任何地方一样将实例存储在列表中。

import random
lst = []
new_node = node(parent,length... etc)

lst.append(new_node)

# assuming you have > 2 nodes:
# pick two random nodes, store in another lst
random_selection = [random.choice(lst) for x in range(2)]

你有什么具体要求吗？

Answer 2

我假设这个＆＃34;节点＆＃34;你的是二叉树的一部分。在这种情况下，您可以遍历树并将引用存储在运行列表中。

有些事情：

arr = []
# Perform tree traversal.
traverse(root_node, arr)
# Now, do something here with the list!

def traverse(node, arr):
    # Traverse the left subtree
    if(node.left is not None):
        traverse(node.left, arr)
    # Traverse the right subtree
    if(node.right is not None):
        traverse(node.right, arr) 
    # Append the node! It can be appended like any other item in the list.
    arr.append(node)

您应该能够将节点（就像其他任何东西一样）附加到列表中，然后根据需要随机选择元素。

Answer 3

我添加一个包含所有节点的类变量（在__init__末尾添加），以及一个随机获取两个节点的类方法：

import random

class Node:
    node_instances = []
    def __init__(self, parent = None, length_to_parent = None, name = None, left = None, right = None, internal = 1, root = 0):
        self.parent = parent # parent node
        self.length_to_parent = length_to_parent # length to the parent node
        self.name = name # name of the node (to-be-defined name if external node(leaf), None if internal node)
        self.left = left # left child
        self.right = right # right child
        self.internal = internal # indicate if the node is an internal node
        self.root = root
        Node.node_instances.append(self)

   @classmethod
   def get_random_instances(cls):
      return random.sample(cls.node_instances, 2)

您可以使用：

n_random = Node.get_random_instances()

Python - 如何从类中随机选择实例

3 个答案: