p">)</span>
  <span class="n">col</span> <span class="o">=</span> <span class="n">df</span><span class="o">.</span><span class="n">as_matrix</span><span class="p">()[:,</span> <span class="nb">int</span><span class="p">(</span><span class="n">ind</span><span class="p">)]</span>
  <span class="n">f</span><span class="p">,</span> <span class="n">t</span><span class="p">,</span> <span class="n">Sxx</span> <span class="o">=</span> <span class="n">spectrogram</span><span class="p">(</span><span class="n">col</sp