为什么我的 class 实例是 int 类型的(我无法访问它的属性)?

Why my class instance is of type int (I can't access its attributes)?

我在Python中创建了一个只有抽象方法的class,然后实现了classBasicMR中的所有方法(不是所有的代码BasicMR 存在于片段中,但方法 test_stationary()self.generate_positions() 中被调用:

class Strategy(object):
    __metaclass__=ABCMeta

    @abstractmethod
    def generate_positions(self):
        raise NotImplementedError("You must implement generatePositions()!")

    @abstractmethod
    def get_positions(self):
        raise NotImplementedError("You must implement getPositions()!")


class BasicMR(Strategy):
    def __init__(self, security, lookback=30):
        self.__securities = []
        self.__securities = security   # it could be either one security or a list of security objects
        self.__positions = self.generate_positions()

    def test_stationary(self, lb=30):
        if not isinstance(self.__securities, list):
            securities = [self.__securities]
        else:
            securities = self.__securities
        prices = [one_stock.get_prices(lb) for one_stock in securities]  # list comprehension
        results = [ts.adfuller(price_series, regression="c", autolag='AIC') for price_series in prices]
        simple_results = [BasicMR.simplify_adf_results(result[1], result[0], result[4]) for result in results]
        if len(simple_results) == 1:
            return simple_results[0]
        else:
            return simple_results

    def generate_positions(self, long_only=False, time_frame=20, max_holding_period = 20):
        result = []
        names = []
        # HERE IS SOME CODE
        return [names, result]

    def get_positions(self):
        return self.__positions

但是,当我创建 BasicMR() 的实例时,我在这一行收到错误:

if not isinstance(self.__securities, list):

错误:

AttributeError: 'int' object has no attribute '_BasicMR__securities'

不知何故,我的 BasicMR class 实例被识别为 int 类型,我不知道如何处理该错误。

您正在 test_stationary class:

>>> BasicMR.test_stationary(42)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "<string>", line 20, in test_stationary
AttributeError: 'int' object has no attribute '_BasicMR__securities'

这将作为 self 参数传入 42,因为该方法未绑定。

您不能创建 class 的实例,因为您没有为generate_positionsget_positions 提供具体实现,但是:

>>> BasicMR([])
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "<string>", line 17, in __init__
  File "<string>", line 6, in generate_positions
NotImplementedError: You must implement generatePositions()!

终于找到问题的根源了。在方法 generate_positions() 中,我调用了实例的方法,就好像它是一个 class 方法一样,而不是写

stationarity_checked_securities = self.test_stationary(time_frame)

我有:

stationarity_checked_securities = BasicMR.test_stationary(time_frame)

test_stationary() 定义为:

def test_stationary(self, lb=30):
    #some code here

也就是说,它不是class方法,但我把它称为好像是。 最后,我的错误看起来很简单,但我对错误文本感到困惑(我是 Python 的新手,我不明白为什么我的 class 实例被称为错误中的“int object”。