title: Count the frequency of characters at a position in a string in a Pandas DataFrame column
body: <p>I have a question related to the <code>df['columnA'].value_counts()</code> method and a previous post here: <a href="https://stackoverflow.com/questions/36004976/count-frequency-of-values-in-pandas-dataframe-column">Count frequency of values in pandas DataFrame column</a></p>
  
  <p>Take this example DataFrame:</p>
  
  <pre><code>fake_data = {'columnA': ['XAVY', 'XAVY', 'XAVY', 'XAVY', 'XAVY', 'AXYV', 'AXYV', 'AXYV', 'AXYV', 'AXYV', 'AXYV']}
  df = pd.DataFrame(fake_data, columns = ['columnA'])
  df
  </code></pre>
  
  <p><strong>I am trying to determine the frequency of each letter (X,A,V,Y) at each position in the string in this column.</strong> </p>
  
  <p>In this example, position 0 would be 54% A, 46% X, position 3 would be 46% Y, 54% V...and so on. </p>