没有传递python树的期望值

时间:2016-06-15 03:43:55

标签: python tree parameter-passing pass-by-reference chess

我找不到一个我可以用来为国际象棋开口创建树形结构的python树,所以我试着写自己的。为了更深入地进入树,我尝试在添加新位置时返回子根,但似乎所有位置都被添加到根目录中,并且我没有像我期望的那样获得对子根的引用,尽管我做了检查,root也有很多孙子。

import chess.pgn

class Node(object):
    children = []
    score = None
    def __init__(self, fen):
        self.fen = fen  
    def add(self, fen):
        for c in self.children:
            if c.fen == (fen):
                print("working")
                return c
        self.children.append(Node(fen))
        return self.children[-1]

root = Node('rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1')
def createTree(fileName):
    pgn = open(fileName)
    game = chess.pgn.read_game(pgn)
    while(game):    
        next_move = game.variations[0]
        fen = next_move.board().fen()
        global root
        currentRoot = root.add(fen)

        while(not next_move.is_end() and next_move.board().fullmove_number <= 5):
            next_move = next_move.variations[0]
            fen = next_move.board().fen()
            currentRoot = currentRoot.add(fen)
            print(currentRoot.children)
        game = chess.pgn.read_game(pgn)

file = r"C:\all.pgn"
createTree(file)
for n in root.children:
    print(n.fen)

1 个答案:

答案 0 :(得分:0)

您的代码失败,因为您误用了class variables.

基本上,当您在任何函数之外声明children时,它在类级别作用域,并且所有Node个对象共享相同的列表。您希望在__init__中将其定义为self.children,以便它在实例级别定义。

class Node:
    def __init__(self, fen):
        self.fen = fen
        self.score = None
        self.children = []
    ...