title: Using a colormap for matplotlib line plots
body: <p>I’d like to employ the reverse Spectral <code>colormap</code> , </p>
  
  <p><a href="https://matplotlib.org/examples/color/colormaps_reference.html" rel="noreferrer">https://matplotlib.org/examples/color/colormaps_reference.html</a></p>
  
  <p>for a lineplot. </p>
  
  <p>This works fine with a hex bin plot::</p>
  
  <pre><code>color_map = plt.cm.Spectral_r
  image = plt.hexbin(x,y,cmap=color_map)
  </code></pre>
  
  <p>but when I do</p>
  
  <pre><code>ax1.plot(x,y, cmp=color_map)
  </code></pre>
  
  <p>this gives me::</p>
  
  <blockquote>
    <p>AttributeError: Unknown property cmap</p>
  </blockquote>
  
  <p>Note, I just want to set the <code>colormap</code> and let <code>matplotliob</code> do the rest; i.e. I don't want to have a <code>color=' argument</code> in the .plot command. </p>