title: Min or Max of pandas data series between two rows
body: <p>I have a pandas dataframe.  Suppose the column names are 'A', 'B', and 'C'.</p>
  
  <p>How can I calculate the min and/or max of data in column 'A' inclusive of only rows m to p?  Where m &lt; p and m != 0 and p &lt; the number of rows in the dataframe.</p>
  
  <p>What if I store the column names in a list and want to iterate over them in a loop and get the max.</p>
  
  <pre><code>colNames = ['A', 'B', 'C']
  for col in colNames:
       # get the max here
  </code></pre>