如何在python的类中正确实现辅助函数

Question

我对 python 还很陌生，我正在尝试设计一个类来解决 N 皇后问题。 这是我的班级定义：

class QueenSolver:

    def genEmptyBoard(self, n):
        # Generates an empty board of n width and n height
        board = []
        for _ in range(n):
            board.append([0 for _ in range(n)])
        return board

    def genLegalBoard(self, q1, q2, n):
        # Returns legal board or false
        board = self.genEmptyBoard(self, n)
        try:
            board[q1[0]][q1[1]] = 'q'
        except IndexError:
            print("Queen placed outside of board constraints")
            return False
        try:
            if board[q2[0]][q2[1]] == 'q':
                print("Queens cannot be placed in the same position")
                return False
            board[q2[0]][q2[1]] = 'Q'
        except IndexError:
            print("Queen placed outside of board constraints")
            return False 
        return board

但是，当我在类之外调用这个方法时，像这样：

board = QueenSolver.genLegalBoard([0, 0], [7, 7], 8)

我收到如下所示的错误：

Exception has occurred: TypeError
QueenSolver.genLegalBoard() missing 1 required positional argument: 'n'

显然我必须在从类定义外部调用“self”变量时提供它？我认为“self”参数不需要任何值，因为它是假设的？我在这里错过了什么？

Answer 1

在调用类的方法之前，需要先实例化QueenSolver类的对象。同时，从board = self.genEmptyBoard(self, n) 中删除self。

class QueenSolver:

    def genEmptyBoard(self, n):
        # Generates an empty board of n width and n height
        board = []
        for _ in range(n):
            board.append([0 for _ in range(n)])
        return board

    def genLegalBoard(self, q1, q2, n):
        # Returns legal board or false
        board = self.genEmptyBoard(n)

        ............
        ............

        return board

QS = QueenSolver()
board = QS.genLegalBoard([0, 0], [7, 7], 8)

输出：

[['q', 0, 0, 0, 0, 0, 0, 0],
 [0, 0, 0, 0, 0, 0, 0, 0],
 [0, 0, 0, 0, 0, 0, 0, 0],
 [0, 0, 0, 0, 0, 0, 0, 0],
 [0, 0, 0, 0, 0, 0, 0, 0],
 [0, 0, 0, 0, 0, 0, 0, 0],
 [0, 0, 0, 0, 0, 0, 0, 0],
 [0, 0, 0, 0, 0, 0, 0, 'Q']]