title: Plot 2 histograms with different length of data points in one graph using matplotlib
body: <p>I have two set of data with one containing around 11 million data points and the another around 5000. I would like to plot them both on one histogram. But because of the difference in size I need to normalise the frequency so I can plot them on the same figure. Below I have simulated what I have done with my data to be able to plot them. I have used the normed=True. </p>
  
  <pre><code>from numpy.random import randn
  import matplotlib.pyplot as plt
  import random
  
  datalist1=[]
  for x in range(1,50000):
    datalist1.append(random.uniform(1,2))
  
  datalist2=randn(5000000)
  
  
  fig= plt.figure(1)
  
  plt.hist(datalist1,bins=20,color='b',alpha=0.3,label='theoretical',histtype='stepfilled', normed=True)
  plt.hist(datalist2,bins=20,alpha=0.5,color='g',label='experimental',histtype='stepfilled',normed=True)
  plt.xlabel("Value")
  plt.ylabel("Normalised Frequency")
  plt.legend()
  plt.show()
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/f5ghs.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/f5ghs.png" alt="enter image description here"></a></p>
  
  <p>Can you please tell me if this is a good way to get around this issue? I would like to match the tallest hight between the two histogram frequencies to be 1 (or 100%).</p>