我每次修改都会重新在notebook上重新执行import及后续语句，但每次都抱有同样的错误
怎么回事，多谢

import numpy as np

class SimpleLinearRegression:
def init(self):
self.a_ = None
self.b_ = None

def fit(self, x_train, y_train):
    assert x_train.ndim == 1, \
        "Simple Linear Regressor can only solve single feature training data"
    assert len(x_train) == len(y_train), \
        "the size of x_train must be equal to the size of y_train"
    x_mean = np.mean(x_train)
    y_mean = np.mean(y_train)
    num = 0.0
    d = 0.0
    for x, y in zip(x_train, y_train):
        num += (x - x_mean) * (y - y_mean)
        d += (x - x_mean) ** 2
    self.a_ = num / d
    self.b_ = y_mean - self.a_ * x_mean
    return self

def predict(self, x_predict):
    return np.array([self._predict(x) for x in x_predict])

def _predict(self, x_single):
    return self.a_ * x_single + self.b_

NameError Traceback (most recent call last)
in
----> 1 req.fit(x,y)

~\Desktop\ML\pycharmtest\SimpleLinearRegeression.py in fit(self, x_train, y_train)
10 assert x_train.ndim == 1,
11 “Simple Linear Regressor can only solve single feature training data”
—> 12 assert len(x_train) == len(y_train),
13 "the size of x_train must be equal to the size of y_train"
14 x_mean = np.mean(x_train)

NameError: name ‘x’ is not defined

1

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