title: Remove Duplicate from Email and export to csv
body: <p>I'm actually clearing my email contact database through the means of python scripting. However, I face some issue while doing so when I remove the duplicate the shape of the data frame still retain even though I check for that there is over 600 duplicates shown. You may refer to the attached codes.</p>
  
  <p>I made use of .drop_duplicates function to remove the duplicate and .shape to show the size again.</p>
  
  <pre><code>import pandas as pd
  import numpy as np
  from pandas import DataFrame
  
  data = pd.read_csv('ToBeSort.csv')
  data.shape
  data['Last Name'].duplicated()
  dupes = data.drop_duplicates(subset=["Last Name"], keep=False)
  print(dupes.shape)
  dupes.to_csv('New.csv')
  </code></pre>
  
  <p>The duplicates still surface after export to new csv. The expected output for the new csv should not have any duplicates email in it.</p>