title: Pandas -Plotting index of data frame against a data frame
body: <p>I need to plot a few index values as addressed in <a href="https://stackoverflow.com/questions/62546861/pandas-calculate-relative-time-from-csv">Pandas - Calculate Relative time from csv</a> <br><br>
  <strong>Sample data</strong><br> It is a huge file,this is just a snippet of it</p>
  <pre><code>highest_layer,transport_layer,src_ip,dst_ip,src_port,dst_port,ip_flag,packet_length,transport_flag,time,timestamp,geo_country,data
      LAN_DISCOVERY,UDP,192.168.1.6,224.0.0.251,5353,5353,0,82,-1,2020-06-10 19:38:08.479232,1591832288479,Unknown,        LAN_DISCOVERY,UDP,fe80::868:621b:c2ff:cee2,ff02::fb,5353,5353,-1,102,-1,2020-06-10 19:38:08.479261,1591832288479,Unknown,        LAN_DISCOVERY,UDP,192.168.1.3,192.168.1.6,5353,5353,16384,409,-1,2020-06-10 19:38:08.506399,1591832288506,Unknown,
      DNS,UDP,192.168.1.6,192.168.1.1,32631,53,0,89,-1,2020-06-10 19:38:08.863846,1591832288863,Unknown,
      DNS,UDP,192.168.1.6,192.168.1.1,31708,53,0,79,-1,2020-06-10 19:38:08.864186,1591832288864,Unknown,
      DNS,UDP,192.168.1.6,192.168.1.1,16807,53,0,79,-1,2020-06-10 19:38:08.866492,1591832288866,Unknown,
      SSDP,UDP,192.168.1.6,239.255.255.250,58185,1900,0,216,-1,2020-06-10 19:38:08.887298,1591832288887,Unknown,
      TCP,TCP,192.168.1.6,208.117.252.25,53725,443,16384,66,16,2020-06-10 19:38:10.107603,1591832290107,Unknown,
      TCP,TCP,192.168.1.6,208.117.252.25,53725,443,16384,66,16,2020-06-10 19:38:10.109444,1591832290109,Unknown,
      TCP,TCP,192.168.1.6,208.117.252.25,53725,443,16384,66,16,2020-06-10 19:38:10.109847,1591832290109,Unknown,
      TCP,TCP,192.168.1.6,208.117.252.25,53725,443,16384,66,16,2020-06-10 19:38:10.111238,1591832290111,Unknown,
      TCP,TCP,192.168.1.6,208.117.252.25,53725,443,16384,66,16,2020-06-10 19:38:10.111676,1591832290111,Unknown,
  </code></pre>
  <p>The code:</p>
  <pre><code>datadis = pd.read_csv('data.txt', sep=',')
  dfd = (datadis[(datadis.src_port == 53725)])
  if not dfd.empty:  # only proceed if the dataframe is not empty
      dfd1 = dfd.drop(columns=['highest_layer', 'transport_layer','ip_flag', 'transport_flag','geo_country','data']).reset_index()
      dfd1.index = dfd1['timestamp'] - dfd1.loc[0,'timestamp']
      dfd2 = dfd1.groupby(['src_ip'])['packet_length'].cumsum()
      dfd2.plot(x='timestamp',y=['packet_length'])
  </code></pre>
  <p>I want to plot relative timestamp(dfd1.index) in the x-axis and dfd2 in y-axis. Say if the difference in time stamp starts at 3000, i want the plot to start from 3000 and not 0(in the example given above it starts at 0) in the x-axis.</p>