title: plotting multiple histograms in grid
body: <p>I am running following code to draw histograms in 3 by 3 grid for 9 varaibles.However, it plots only one variable.</p>
  
  <pre><code>import pandas as pd
  import numpy as np
  import matplotlib.pyplot as plt
  
  def draw_histograms(df, variables, n_rows, n_cols):
      fig=plt.figure()
      for i, var_name in enumerate(variables):
          ax=fig.add_subplot(n_rows,n_cols,i+1)
          df[var_name].hist(bins=10,ax=ax)
          plt.title(var_name+"Distribution")
          plt.show()
  </code></pre>