title: Filter CSV File with Pandas/Python
body: <p>I have a CSV file, I wanted to filter it where I keep just rows where I have values in row "d" bigger then 0. </p>
  
  <p><strong>File:</strong> </p>
  
  <pre><code>  index  value    d
  0    975  25.35   5
  1    976  26.28   4
  2    977  26.24   1
  3    978  25.76   0
  4    979  26.08   0
  </code></pre>
  
  <p>I used pandas to do that, but It didn't work out:  </p>
  
  <pre><code>df = pd.read_csv("ThisFileL.csv")
  df = df[(df["d"]&gt;0)]
  </code></pre>
  
  <p>I used other approach as well, but it's too long to process a file of 600mb.</p>
  
  <pre><code>with open("ThisFileL.csv", 'rb') as source:
      writer = csv.writer(source)
      for line in source:
          if line.d &gt; 0 :
                writer.writerow(headers)
  </code></pre>