title: drop 100 percent match duplicates in pandas
body: <p>This is my CSV sample:</p>
  <pre><code>Channel|Store_ID|Store_Code|Store_Type|Order_ID|Order_Date|Member_ID|Member_Tier|Coupon_ID|Order_Total|Material_No|Material_Name|Size|Quantity|Unit_Price|Line_Total|Discount_Amount
  ECOM|ECOM|ECOM|ECOM|RBSKA1907002995|2019-07-23 00:06:00||||1064.00|DM7564|SPT Full Zip|750|2.00|399.00|168.00|231.00
  ECOM|ECOM|ECOM|ECOM|BSKA1907002995|2019-07-23 00:06:00||||1064.00|DV1361|YB TR COOL TEE|200|1.00|199.00|84.00|115.00
  ECOM|ECOM|ECOM|ECOM|BSKA1907002995|2019-07-23 00:06:00||||1064.00|DU7699|TAN TR UT PANT|690|1.00|499.00|210.00|289.00
  ECOM|ECOM|ECOM|ECOM|BSKA1907002995|2019-07-23 00:06:00||||1064.00|DY8700|AI PNT LWFT|690|1.00|399.00|196.00|203.00
  ECOM|ECOM|ECOM|ECOM|BSKA1907002995|2019-07-23 00:06:00||||1064.00|DU8438|COPA HIST GFX T|690|1.00|229.00|112.00|117.00
  ECOM|ECOM|ECOM|ECOM|BSKA1907002995|2019-07-23 00:06:00||||1064.00|DU8324|CLASS ACTION JK|350|1.00|599.00|294.00|305.00
  ECOM|ECOM|ECOM|ECOM|BSKA1907003632|2019-07-28 12:31:00||||798.00|DX3689|DRESS|500|1.00|699.00|294.00|405.00
  OR|CBF|137|CS|7040219154|2021-03-06 21:11:10|00100972490|||798.00|GP5581|W CE 3S WB|897|1.00|499.00|399.00|100.00
  OR|CBF|137|CS|7040219154|2021-03-06 21:11:10|00100972490|||798.00|GK9370|M FAVS Q2 WB|710|1.00|499.00|399.00|100.00
  </code></pre>
  <p>I tried to drop duplicates in pandas but I got something wrong. I can't drop the 100% match duplicate and something can't display.
  This is my code:</p>
  <pre><code>import csv
  import re
  import pandas as pd
  
  df = pd.read_csv('CSV_Sample.csv', delimiter='|')
  df = df[['Channel','Store_Code','Order_ID','Order_Date','Member_ID','Coupon_ID','Order_Total']]
  df.drop_duplicates(subset =&quot;Order_ID&quot;,keep = False, inplace = True)
  df.to_csv('transaction_header.csv',na_rep='',sep = '|',index = None)
  </code></pre>
  <p>And the result:</p>
  <pre><code>Channel|Store_Code|Order_ID|Order_Date|Member_ID|Coupon_ID|Order_Total
  ECOM|ECOM|RBSKA1907002995|2019-07-23 00:06:00|||1064.0
  ECOM|ECOM|BSKA1907003632|2019-07-28 12:31:00|||798.0
  </code></pre>
  <p>But expect result:</p>
  <pre><code>Channel|Store_Code|Order_ID|Order_Date|Member_ID|Coupon_ID|Order_Total
  ECOM|ECOM|RBSKA1907002995|2019-07-23 00:06:00|||1064.0
  ECOM|ECOM|BSKA1907002995|2019-07-23 00:06:00|||1064.0
  ECOM|ECOM|BSKA1907003632|2019-07-28 12:31:00|||798.0
  OR|CBF|137|CS|7040219154|2021-03-06 21:11:10|00100972490|||798.00
  </code></pre>
  <p>Any help would be very much appreciated.</p>