title: Understanding why drop.duplicates() Is not working
body: <p>Suppose I have a 2-row pandas dataframe that I acquired by subsetting a larger dataframe.</p>
  
  <pre><code>             TransID     rev    offer         qs   lt         chan  
  212    RTSO118981094  737.24  ABCXCS           3  d382        O78   
  53311  RTSO118981094  737.24  ABCXCS           3  d382        O78   
  </code></pre>
  
  <p>The rev is a float that has been rounded to 2 decimal places.</p>
  
  <p>The 2 rows look identical and when I do a "diff" there is no output.  Even so,</p>
  
  <pre><code>df = df.drop_duplicates() 
  </code></pre>
  
  <p>has no effect.  Their fields are all the same length.</p>
  
  <p>How to get this to work?</p>