title: plotting the center of a k-means cluster to be the same color as its cluster points
body: <p>I am able to plot all the data points of a kmeans cluster such that clusters are denoted by different colors. However now i want to also plot the center of the cluster to be the same color as the cluster points. 
  Here is my code:</p>
  
  <pre><code>num_clusters=5
  data2D = pca.transform(X)
  centers2D = pca.transform(km.cluster_centers_)
  labels=km.labels_
  colors=['#000000','#FFFFFF','#FF0000','#00FF00','#0000FF']
  col_map=dict(zip(set(labels),colors))
  label_color = [col_map[l] for l in labels]
  plt.scatter( data2D[:,0], data2D[:,1], c=label_color) # This plots the cluster points.
  </code></pre>
  
  <p>Now the problem lies here, How do i also plot the cluster center points to be the same color as the points? Specifically, what should i use for <code>c</code> ?</p>
  
  <pre><code>plt.scatter(centers2D[:,0], centers2D[:,1],  marker='x', s=200, linewidths=2, c=label_color)
  </code></pre>
  
  <p>using c=label_color doesnt work because centers2D is a list of coordinates as shown below. How do i map the coordinates to the same colors i map to integers for the first scatter plot?</p>
  
  <pre><code>print centers2D
  
  [[ 0.03563292 -0.09528218]
   [ 0.05799584  0.01593253]
   [ 0.02265664  0.05109819]
   [ 0.09457535 -0.11127898]
   [-0.16129666  0.00428571]]
  </code></pre>