title: Drawing 6 graphs from a text file in CERN ROOT
body: <p>I am new in ROOT.<br>
  I have a text file contains 9 columns and 96 rows.<br>
  I want to read the 1st, 4th and 5th columns and store the values in x,y,ey.</p>
  
  <p>I would like to plot 6 graphs, one for each different value of the third column of the original text file.</p>
  
  <p>For example the rows 1,4,7 etc have the same value in 3rd column (in my case -0.7):  </p>
  
  <p><code>{x=(row=1column=1,row=7column=1,row=13column=1, row=19column=1.......)}</code>,<br>
  <code>{y=(row=1column=4,row=7column=4,row=13column=4, row=19column=4.....)}</code> and    <code>{ey=(row=1column=5,row=7column=5,row=13column=5, row=19column=5.....)}</code>  </p>
  
  <p>(Here below a picture is attached to show the data).  </p>
  
  <p><img src="https://i.stack.imgur.com/qPAMn.png" alt="Data"></p>
  
  <p>Please let me know how to do it.<br>
  Thank you very much in advance!  </p>