title: gnuplot conditional plotting: plot col A:col B if col C == x
body: <p>How can I do this in gnuplot:</p>
  
  <pre><code>plot "test.csv" using 1:2 if value_in_column_3 == 80.0
  </code></pre>
  
  <p>It should only select those rows where column 3 == 80.0 and ignore all other rows (It should not plot a 0 for the other rows, simply ignore them)</p>
  
  <p>Thanks in advance.</p>