title: Select negative values from a Data Frame, using R
body: <p>I have the following <code>data.frame</code> called <code>best100_gene</code>: </p>
  
  <p><img src="https://i.stack.imgur.com/orYZY.png" alt="best100_gene"></p>
  
  <p>I want to select only the lines where <code>Data_PCA$ind$coord[, 2] &lt; 0</code>. I tried the following command: </p>
  
  <pre><code>gene_neg = best100_gene[which("Data_PCA$ind$coord[, 2]" &lt; 0, )]
  </code></pre>
  
  <p>But it doesn't work! I tried several other options but they did not work either. </p>