python - 使用类在 python 中创建图形数据结构

Question

我正在尝试创建某种类型的类，该类足够通用，可用于树和图。

class Node:
    def __init__(self, value, children=[]):
        self.value = value
        self.children = children

    def add_child(self, child):
        self.children.append(child)

    def add_children(self, list_of_children):
        for child in list_of_children:
            self.add_child(child)

def letterGraph():
    a = Node('A')
    b = Node('B')
    c = Node('C')
    d = Node('D')
    c = Node('C')
    e = Node('E')
    f = Node('F')
    g = Node('G')

    a.add_children([b, c])
    b.add_children([a, d, e])
    c.add_children([a, d])
    d.add_children([b, c, e, g, f])
    e.add_children([b, d, g])
    f.add_children([d, g])
    g.add_children([e, d, f])

    return a

它似乎在树上工作得很好，但对于图来说，当它向当前节点添加一个子节点时，它也会将同一个子节点添加到当前节点的子节点中。

example:

current_node: a

a.add_children([b,c])

current_node.children: [b,c]

b.children: [b,c]`

Answer 1

我个人根本不会在构造函数中调用它。你不使用那你为什么要把它放在那里呢？

使用__repr__也有助于使其在测试时更具可读性。

class Node:
    def __init__(self, value):    # Take children out of constructor
        self.value = value
        self.children = []     # Initialise children in the function

    def add_child(self, child):
        self.children.append(child)

    def add_children(self, list_of_children):
        for child in list_of_children:
            self.add_child(child)

    def __repr__(self): 
        return self.value    # I am not a machine 

def letterGraph():
    a = Node('A')
    b = Node('B')
    c = Node('C')
    d = Node('D')
    c = Node('C')
    e = Node('E')
    f = Node('F')
    g = Node('G')

    a.add_children([b, c])
    b.add_children([a, d, e])
    c.add_children([a, d])
    d.add_children([b, c, e, g, f])
    e.add_children([b, d, g])
    f.add_children([d, g])
    g.add_children([e, d, f])

    print(a.children)
    print(b.children)


letterGraph()