title: Replace integers in dataframe column w/ 'Y'
body: <p>I have a dataframe w/ two columns: Account, Bought Food that I created with a pivot table to condense each account into one row. Right now it is showing me the total food bought as a number, but can I have alter the data to to show just a 'Y' where there is an integer (I am already using the fillna function to replace NaN w/ No).</p>
  
  <p>Example:</p>
  
  <p>Current:
  AcctNo BoughtFood
  1ABC 5
  2ABD N
  3DBC 7</p>
  
  <p>Want:
  AcctNo BoughtFood
  1ABC Y
  2ABD N
  3DBC Y</p>