title: AttributeError: LinearRegression object has no attribute 'coef_'
body: <p>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.</p>
  
  <pre><code>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()
  </code></pre>
  
  <p>After I had all this set up I ran the following command, and it returned the proper output:</p>
  
  <pre><code>In [68]: print('Number of coefficients:', len(lm.coef_)
  
  Number of coefficients: 13
  </code></pre>
  
  <p>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.</p>
  
  <pre><code>In [70]: print('Number of coefficients:', len(lm.coef_))
  
  Traceback (most recent call last):
  
   File "&lt;ipython-input-70-5ad192630df3&gt;", line 1, in &lt;module&gt;
  print('Number of coefficients:', len(lm.coef_))
  
  AttributeError: 'LinearRegression' object has no attribute 'coef_'
  </code></pre>