title: Plot data without interpolation from former x value
body: <p>I am doing some particle tracking at the moment. Therefore I want to plot the distribution and the cumulative function of the passing particles. </p>
  
  <p>When I plot the distribution, my plot always starts one time step to early.
  Is there a way to just plot the event as a kind of peak, without any interpolation on the x axis? </p>
  
  <p>Short example data is attached...</p>
  
  <pre><code>time = [ 0.,1.,2.,3.,4.,5.,6.,7.,8.,9.]
  counts = [0,0,1,0,2,0,0,0,1,0]
  cum = [ 0.,0.,0.25,0.25,0.75,0.75,0.75,0.75,1.,1.]
  
  ax1 = plt.subplot2grid((1,2), (0, 0), colspan=1)
  ax1.plot(time, counts, "-", label="Density")
  ax1.set_xlim([0,time[-1]])
  ax1.legend(loc = "upper left", frameon = False)
  ax1.grid()
  
  ax2 = plt.subplot2grid((1,2), (0, 1), rowspan=1)
  ax2.step(time, cum, "r",where='post', label="Sum")
  ax2.legend(loc = "upper left", frameon = False)
  ax2.set_ylim([-0.05,1.05])
  ax2.set_xlim([0,time[-1]])
  ax2.grid()
  
  plt.suptitle("Particle distribution \n")
  plt.show()
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/ZK7VY.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/ZK7VY.png" alt="enter image description here"></a></p>
  
  <p>Thanks for any help!</p>