Python AttributeError: LinearRegression 对象没有属性“coef_”
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AttributeError: LinearRegression object has no attribute 'coef_'
提问by Destroxia
I've been attempting to fit this data by a Linear Regression, following a tutorial on bigdataexaminer. Everything was working fine up until this point. I imported LinearRegression from sklearn, and printed the number of coefficients just fine. This was the code before I attempted to grab the coefficients from the console.
按照 bigdataexaminer 的教程，我一直在尝试通过线性回归拟合这些数据。到目前为止，一切都运行良好。我从 sklearn 导入了 LinearRegression，并很好地打印了系数的数量。这是我尝试从控制台获取系数之前的代码。
import numpy as np
import pandas as pd
import scipy.stats as stats
import matplotlib.pyplot as plt
import sklearn
from sklearn.datasets import load_boston
from sklearn.linear_model import LinearRegression
boston = load_boston()
bos = pd.DataFrame(boston.data)
bos.columns = boston.feature_names
bos['PRICE'] = boston.target
X = bos.drop('PRICE', axis = 1)
lm = LinearRegression()
After I had all this set up I ran the following command, and it returned the proper output:
完成所有这些设置后，我运行了以下命令，它返回了正确的输出：
In [68]: print('Number of coefficients:', len(lm.coef_)
Number of coefficients: 13
However, now if I ever try to print this same line again, or use 'lm.coef_', it tells me coef_ isn't an attribute of LinearRegression, right after I JUST used it successfully, and I didn't touch any of the code before I tried it again.
但是，现在如果我再次尝试打印同一行，或使用“lm.coef_”，它会告诉我 coef_ 不是 LinearRegression 的属性，就在我成功使用它之后，我没有触及任何在我再次尝试之前的代码。
In [70]: print('Number of coefficients:', len(lm.coef_))
Traceback (most recent call last):
File "<ipython-input-70-5ad192630df3>", line 1, in <module>
print('Number of coefficients:', len(lm.coef_))
AttributeError: 'LinearRegression' object has no attribute 'coef_'
回答by jakevdp
The coef_attribute is created when the fit()method is called. Before that, it will be undefined:
该coef_属性是在fit()调用方法时创建的。在此之前，它将是未定义的：
>>> import numpy as np
>>> import pandas as pd
>>> from sklearn.datasets import load_boston
>>> from sklearn.linear_model import LinearRegression
>>> boston = load_boston()
>>> lm = LinearRegression()
>>> lm.coef_
---------------------------------------------------------------------------
AttributeError Traceback (most recent call last)
<ipython-input-22-975676802622> in <module>()
7
8 lm = LinearRegression()
----> 9 lm.coef_
AttributeError: 'LinearRegression' object has no attribute 'coef_'
If we call fit(), the coefficients will be defined:
如果我们调用fit()，系数将被定义：
>>> lm.fit(boston.data, boston.target)
>>> lm.coef_
array([ -1.07170557e-01, 4.63952195e-02, 2.08602395e-02,
2.68856140e+00, -1.77957587e+01, 3.80475246e+00,
7.51061703e-04, -1.47575880e+00, 3.05655038e-01,
-1.23293463e-02, -9.53463555e-01, 9.39251272e-03,
-5.25466633e-01])
My guess is that somehow you forgot to call fit()when you ran the problematic line.
我的猜测是，fit()当您运行有问题的线路时，不知何故您忘记了打电话。
