title: Access a particular row,column in a csr_matrix
body: <p>I have a sparse matrix in csr format (which makes sense for my purposes, as it has lots of rows but relatively few columns, ~8million x 90).</p>
  
  <p>My question is, what's the most efficient way to access a particular value from the matrix given a row,column tuple? I can quickly get a row using <code>matrix.getrow(row)</code>, but this also returns 1-row sparse matrix, and accessing the value at a particular column seems clunky. The only reliable method I've found to get a particular matrix value, given the row and column, is:</p>
  
  <pre><code>matrix.getrow(row).todense().A1[column]
  </code></pre>
  
  <p>But this seems overly verbose and complicated. Is there a simpler/faster method I'm missing?</p>