title: Pandas groupby results on the same plot
body: <p>I am dealing with the following data frame (only for illustration, actual df is quite large):</p>
  
  <pre><code>   seq          x1         y1
  0  2           0.7725      0.2105
  1  2           0.8098      0.3456
  2  2           0.7457      0.5436
  3  2           0.4168      0.7610
  4  2           0.3181      0.8790
  5  3           0.2092      0.5498
  6  3           0.0591      0.6357
  7  5           0.9937      0.5364
  8  5           0.3756      0.7635
  9  5           0.1661      0.8364
  </code></pre>
  
  <p>Trying to plot multiple line graph for the above coordinates (x as "x1 against y as "y1").</p>
  
  <p>Rows with the same "seq" is one path, and has to be plotted as one separate line, like all the x, y coordinates corresponding the seq = 2 belongs to one line, and so on. </p>
  
  <p>I am able to plot them, but on a separate graphs, I want all the lines on the same graph, Using <strong>subplots</strong>, but not getting it right. </p>
  
  <pre><code>import matplotlib as mpl
  import matplotlib.pyplot as plt
  
  %matplotlib notebook
  
  df.groupby("seq").plot(kind = "line", x = "x1", y = "y1")
  </code></pre>
  
  <p>This creates 100's of graphs (which is equal to the number of unique seq). Suggest me a way to obtain all the lines on the same graph.</p>
  
  <p>**UPDATE*</p>
  
  <p>To resolve the above problem, I implemented the following code:</p>
  
  <pre><code>     fig, ax = plt.subplots(figsize=(12,8))
       df.groupby('seq').plot(kind='line', x = "x1", y = "y1", ax = ax)
       plt.title("abc")
       plt.show()
  </code></pre>
  
  <p>Now, I want a way to plot the lines with specific colors. I am clustering path from seq = 2 and 5 in cluster 1; and path from seq = 3 in another cluster.</p>
  
  <p>So, there are two lines under cluster 1 which I want in red and 1 line under cluster 2 which can be green.</p>
  
  <p>How should I proceed with this?</p>