title: Partially transparent scatter plot, but with a solid color bar
body: <p>In Python, with Matplotlib, how to simply do a scatter plot with transparency (alpha &lt; 1), but with a color bar that represents their color value, but has alpha = 1?</p>
  
  <p>Here is what one gets, with <code>from pylab import *; scatter(range(10), arange(0, 100, 10), c=range(10), alpha=0.2); color_bar = colorbar()</code>:</p>
  
  <p><img src="https://i.stack.imgur.com/jxU3H.png" alt="alt text"></p>
  
  <p>How can the color bar be made non-transparent?</p>
  
  <p><strong>PS</strong>: I tried <code>color_bar.set_alpha(1); draw()</code>, but this did not do anything…</p>