title: Using 'real values' in imshow in python
body: <p>I would like to plot a heatmap using the <code>imshow()</code> module, however I am struggling to get it to work the way I would like to. My data is stored in <code>pandas</code> dataframe which consists of 100-1000 columns, each column with 201 rows. The first row in each column is a value I would like to use on my x-axis, whereas remaining 200 rows are the data points to be used in <code>imshow</code> plot. </p>
  
  <p>Here is the structure of my dataframe (the values do eventually increase from 0.0000):
  <a href="https://i.stack.imgur.com/xyMVw.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/xyMVw.png" alt="enter image description here"></a></p>
  
  <p>The first column is just a counter between 0-200 - I usually drop it when I load the data since it is the same as the row index. The problem I currently have is in the plot, when I use <code>imshow()</code> to plot my figure, it uses the row and column index as the axis ticks. This is fine for my Y axis, since it is the same as my values in column 0; the problem is with the X-axis which has index values between 1-1000, whereas I would like to plot it on axis with actual values of X (i.e. 381.3, 393.3, 200.6 etc). How could I accomplish that? </p>
  
  <p>Currently this is what I get:
  <a href="https://i.stack.imgur.com/NZocB.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/NZocB.png" alt="enter image description here"></a></p>
  
  <p>Here is the code I use so far:</p>
  
  <pre><code>rawData = pd.read_csv('heme_mpc_drift2.csv', delimiter=',')
  rawData_drop=rawData.drop(rawData[[101,102]], axis=1, inplace=False)
  xaxis = rawData_drop.ix[0,1:]
  yaxis = rawData_drop.ix[1:,0]
  plt.figure(figsize=[10,5])
  plt.ylim([200,0])
  plt.imshow(rawData_drop, cmap=cmaps.plasma, interpolation="none", aspect='auto', vmax=500000)
  plt.colorbar()
  plt.show()
  </code></pre>
  
  <p>I was hoping to use the <code>xaxis</code> and <code>yaxis</code> in the <code>imshow()</code> somewhere, however haven't figured out where. I have tried using <code>extent</code> in <code>imshow()</code> but it only converts the values from range of 1-100 to whatever new range I give it. </p>
  
  <p>I would appreciate any suggestions.</p>
  
  <p>EDIT 1: 
  Added an example of what I am looking for:
  <a href="https://i.stack.imgur.com/AI7jL.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/AI7jL.png" alt="enter image description here"></a></p>