title: Error with scikit-learn.preprocessing: ImportError: No module named sklearn
body: <p>I wanted to normalize the values of an array to the range between <code>0</code> and <code>1</code>. I am running the code on <code>jupyter notebook</code> with <code>python 2</code>. I have already installed <code>scikit learn</code> , however, it is showing the following error:</p>
  
  <pre><code>import sklearn
  from sklearn import preprocessing
  min_max_scaler = preprocessing.MinMaxScaler()
  f = min_max_scaler.fit_transform(f)
  plt.imshow(f)
  plt.show()
  
  ImportError                               Traceback (most recent call last)
  &lt;ipython-input-34-a856ee09a5a1&gt; in &lt;module&gt;()
       28 
       29 #minmax scaling by scikit learn
  ---&gt; 30 import sklearn
       31 from sklearn import preprocessing
       32 min_max_scaler = preprocessing.MinMaxScaler()
  
  ImportError: No module named sklearn
  </code></pre>
  
  <p>Could someone please give some hints what is the reason?</p>