Question

我正在尝试在python中编写迷宫生成器：迷宫由2D整数列表组成：列表用于表示此迷宫在我的世界中的样子，因此每个单元实际上都位于x的两个位置和y坐标是奇数。

我编写的用于修改“Maze”类中单元格值的方法不断抛出ValueError: list.remove(x): x not in list异常。这是代码：

def setCell(self, x, y, request):
    query = Maze.blocks[(2*x)+1][(2*y)+1]
    if 0 <= x < (Maze.length-1)/2 and 0 <= y < (Maze.height-1)/2:
        if request > query:
            Maze.blocks[(2*x)+1][(2*y)+1] = request
            print('changed cell ' + str(x) + ', ' + str(y) + ' to ' + str(request))
            P = Point(x, y)
            if request == Maze.WORKING: #WORKING and DONE are constants
                Maze.List.append(P) 
                print(Maze.List) #debugging purposes
            elif request == Maze.DONE:
                print('trying to remove ' + str(P))

                Maze.List.remove(Point(P.x, P.y))
                #^^^here is the error.
                #I tried to use Maze.List.remove(P),
                #but that threw the exact same error.

                print(Maze.List)
            else:
                print('should NOT be writing ' + str(request) + ' to ' + str(query) + '!')
            return True
        else:
            print(str(request) + ' cannot overwrite ' + str(query))
            return False
    else:
        print('invalid range for cell. req was ' + str(x) + ', ' + str(y))
        return False

这是我运行代码的时候（我有方法打印出迷宫在添加每个点之后的样子：

changed cell 2, 7 to 1
[Point(0, 8), Point(0, 7), Point(0, 9), Point(1, 9), Point(1, 7), Point(2,7)]
$ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ 
$ * @ * @ * @ * @ * @ * @ * @ * @ * @ * $ 
$ @ $ @ $ @ $ @ $ @ $ @ $ @ $ @ $ @ $ @ $ 
$ * @ * @ * @ * @ * @ * @ * @ * @ * @ * $ 
$ @ $ @ $ @ $ @ $ @ $ @ $ @ $ @ $ @ $ @ $ 
$ * @ * @ * @ * @ * @ * @ * @ * @ * @ * $ 
$ @ $ @ $ @ $ @ $ @ $ @ $ @ $ @ $ @ $ @ $ 
$ * @ * @ * @ * @ * @ * @ * @ * @ * @ * $ 
$ @ $ @ $ @ $ @ $ @ $ @ $ @ $ @ $ @ $ @ $ 
$ * @ * @ * @ * @ * @ * @ * @ * @ * @ * $ 
$ @ $ @ $ @ $ @ $ @ $ @ $ @ $ @ $ @ $ @ $ 
$ * @ * @ * @ * @ * @ * @ * @ * @ * @ * $ 
$ @ $ @ $ @ $ @ $ @ $ @ $ @ $ @ $ @ $ @ $ 
$ * @ * @ * @ * @ * @ * @ * @ * @ * @ * $ 
$ @ $ @ $ @ $ @ $ @ $ @ $ @ $ @ $ @ $ @ $ 
$ : : : : : @ * @ * @ * @ * @ * @ * @ * $ 
$ : $ @ $ @ $ @ $ @ $ @ $ @ $ @ $ @ $ @ $ 
$ : @ * @ * @ * @ * @ * @ * @ * @ * @ * $ 
$ : $ @ $ @ $ @ $ @ $ @ $ @ $ @ $ @ $ @ $ 
$ : : : @ * @ * @ * @ * @ * @ * @ * @ * $ 
$ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ 

changed cell 0, 7 to 2
trying to remove (0, 7)
Traceback (most recent call last):
  File "/Users/jim/PycharmProjects/MC_Maze/Maze.py", line 400, in <module>
    if not M.setCell(A.x, A.y, Maze.DONE):
  File "/Users/jim/PycharmProjects/MC_Maze/Maze.py", line 104, in setCell
    Maze.List.remove(Point(P.x, P.y))
ValueError: list.remove(x): x not in list

你可以从列表中看到Point（0,7）在列表中，但是python似乎不同意。作为像python这样的低级语言的新手，我不知道为什么这不起作用。提前谢谢！

Answer 1

您的Point类是否定义__eq__（用于相等性检查）？将相同的值放入类中并不意味着该类等于具有相同值的另一个值。以下显示了我认为您的代码出错的地方：

>>> class MyClass(object):
...     def __init__(self, my_var):
...             self.my_var = my_var
...
>>> my_obj1 = MyClass("a value")
>>> my_obj2 = MyClass("a value")
>>> my_obj1 == my_obj2
False

尝试在Point上写一个unit test表示相等，以便检查它是否符合您的预期。

从列表中删除点对象：ValueError：list.remove（x）：x不在列表中

1 个答案: