title: Unable to plot scatter plot because of TypeError
body: <p>I have a dataset, in which i will be using only a single column to apply kmeans clustering. However while plotting the graph, i am getting "numpy.ndarray". I tried converting to float, but still facing the same issue</p>
  
  <p>Dataframe:</p>
  
  <pre><code> Brim
   1234.5
   345
   675.7
   120
   110
  </code></pre>
  
  <p>Code:</p>
  
  <pre><code> from sklearn.cluster import KMeans
   import numpy as np
   km = KMeans(n_clusters=4, init='k-means++',n_init=10)
   km.fit(df1)
   x = km.fit_predict(df1)
   x
   array([0, 0, 0, ..., 3, 3, 3])
  
   np.shape(x)
   (1097,)
  
    import matplotlib.pyplot as plt
    %matplotlib inline
  
    plt.scatter(df1[x ==1,0], df1[x == 0,1], s=100, c='red')
    plt.scatter(df1[x ==1,0], df1[x == 1,1], s=100, c='black')
    plt.scatter(df1[x ==2,0], df1[x == 2,1], s=100, c='blue')
    plt.scatter(df1[x ==3,0], df1[x == 3,1], s=100, c='cyan')
  </code></pre>
  
  <p>Error:</p>
  
  <pre><code>   ---------------------------------------------------------------------------
      TypeError                                 Traceback (most recent call last)
      &lt;ipython-input-62-5f0966ccc828&gt; in &lt;module&gt;()
       1 import matplotlib.pyplot as plt
       2 get_ipython().run_line_magic('matplotlib', 'inline')
    ----&gt; 3 plt.scatter(df1[x ==1,0], df1[x == 0,1], s=100, c='red')
       4 plt.scatter(df1[x ==1,0], df1[x == 1,1], s=100, c='black')
       5 plt.scatter(df1[x ==2,0], df1[x == 2,1], s=100, c='blue')
  
       ~\AppData\Local\Continuum\anaconda3\lib\site-packages\pandas\core\frame.py in __getitem__(self, key)
       2137             return self._getitem_multilevel(key)
       2138         else:
     -&gt;2139             return self._getitem_column(key)
       2140 
       2141     def _getitem_column(self, key):
  
      ~\AppData\Local\Continuum\anaconda3\lib\site- 
   packages\pandas\core\frame.py in _getitem_column(self, key)
       2144         # get column
       2145         if self.columns.is_unique:
    -&gt; 2146             return self._get_item_cache(key)
       2147 
       2148         # duplicate columns &amp; possible reduce dimensionality
  
     ~\AppData\Local\Continuum\anaconda3\lib\site- packages\pandas\core\generic.py in _get_item_cache(self, item)
       1838         """Return the cached item, item represents a label indexer."""
       1839         cache = self._item_cache
    -&gt; 1840         res = cache.get(item)
       1841         if res is None:
       1842             values = self._data.get(item)
  
     TypeError: unhashable type: 'numpy.ndarray'
  </code></pre>