为什么我偶尔会返回 NoneType 错误？

Question

我无法理解 Attribute Error: None Type 我的程序的来源。我正在运行进行一系列模拟，大多数时候当我运行 <50 循环时，不会出现错误。然而，偶尔，或者在更大的模拟中，我 returned 了一个错误，它会说...

AttributeError: 'NoneType' object has no attribute 'name'
AttributeError: 'NoneType' object has no attribute 'regular_score'

这些属性已较早实例化，并且在大多数模拟中都正常工作。

该项目的目标是 return 一个包含所有模拟摘要的 DataFrame。下面是 DataFrame 的子集。

                  Projected Finish  Chance of Finals  Chance at a Bye  Chance of First  Chance of Last
Player_A              3.88                     80.0             36.0         40.0         0.0
Player_B              4.56                     76.0             28.0         12.0         8.0
Player_C              5.40                     68.0             20.0         4.0          12.0
Player_D              5.72                     60.0             12.0         4.0          8.0
Player_E              5.88                     64.0             12.0         4.0          20.0

错误的回溯是：

Traceback (most recent call last):
  File "/Users/tomrogers/Desktop/Python/primary/tempCodeRunnerFile.py", line 512, in <module>
    finishing_postions(250)
  File "/Users/tomrogers/Desktop/Python/primary/tempCodeRunnerFile.py", line 454, in finishing_postions
    winner.append(grand_final())
  File "/Users/tomrogers/Desktop/Python/primary/tempCodeRunnerFile.py", line 373, in grand_final
    player_1 = first_preliminary()
  File "/Users/tomrogers/Desktop/Python/primary/tempCodeRunnerFile.py", line 350, in first_preliminary
    player_2_score = player_2.regular_score()
AttributeError: 'NoneType' object has no attribute 'regular_score'

它指向这个函数，但如您所见，我没有调用不存在的属性。

def grand_final():

    player_1 = first_preliminary()
    player_2 = second_preliminary()

    # print(
    #     f"{'Simulating Grand Final'} {'Between' + ' ' + player_1.name + ' & ' + player_2.name} ")
    player_1_score = player_1.regular_score()
    player_2_score = player_2.regular_score()

    if player_1_score > player_2_score:
        return player_1.name
    if player_2_score > player_1_score:
        return player_2.name

我对此的理解是似乎调用了一个不具有该属性的变量，但是当循环成功运行s 通过 25 次左右的模拟时，没有错误出现并且机会第一列/最后一列的机会均 = 100，这表明没有隐藏变量被调用。

这是 10 个对象之一的示例，所有 10 个都遵循相同的顺序。

Player_A = TL(name='Player A', scores=np.array([]))

我确实想过尝试一下，除了捕获错误的顺序，但我不确定如何使用 returning NoneType.

如果我可以提供更多详细信息，请告诉我。

非常感谢！

编辑：

def second_preliminary():
    player_1 = eval(ladder['Coach'].iloc[1])
    player_2 = second_elimination()

    player_1_score = player_1.regular_score()
    player_2_score = player_2.regular_score()

    if player_1_score > player_2_score:
         return player_1
    if player_2_score > player_1_score:
         return player_2

def second_elimination():
""" simulate the finals """

    player_1 = eval(ladder['Coach'].iloc[2])
    player_2 = eval(ladder['Coach'].iloc[4])

    player_1_score = player_1.regular_score()
    player_2_score = player_2.regular_score()

    if player_1_score > player_2_score:
         return player_1
    if player_2_score > player_1_score:
         return player_2

一个模拟的 returned 阶梯样本是：

print(ladder)

           Coach     F     A     Pct  Pts
Team                                             
Player_A   Player A  7316  7023  104.17   16
Player_B   Player B  7619  7436  102.46   16
Player_C   Player C  7524  7272  103.47   12
Player_D   Player D  7116  7102  100.20   12
Player_E   Player E  7343  7593   96.71   12
Player_F   Player F  7616  7276  104.67    8
Player_G   Player G  7763  7532  103.07    8
Player_H   Player H  7507  7342  102.25    8
Player_I   Player I  7111  7681   92.58    8
Player_J   Player J  7244  7902   91.67    0

Answer 1

我相信我已经解决了这个问题，我认为这与某些函数的疏忽有关，在这些函数中我不小心调用了两个 if 语句，而不是 if、elif 和 else。一旦我纠正我不再遇到这个问题。

谢谢！

为什么我偶尔会返回 NoneType 错误？

Why am I sporadically being returned a NoneType Error?

python

attributes

object

pandas

nonetype