title: How to slice a csr_matrix by certain list of rows/columns?
body: <p>Suppose my csr_matrix is </p>
  
  <pre><code>I = [0, 1, 3 ,4 ,5, 0, 3]
  J = [1, 3 , 4, 9 ,1 , 0, 8]
  V = [1]*6
  V.append(0)
  data=sparse.coo_matrix((V,(I,J)),shape=(7,10)).tocsr()
  </code></pre>
  
  <p>which outputs</p>
  
  <pre><code>(0, 0)  1
  (0, 1)  1
  (1, 3)  1
  (3, 4)  1
  (3, 8)  0
  (4, 9)  1
  (5, 1)  1
  </code></pre>
  
  <p>So,I want to get entries with specific list of rows/columns. For example:</p>
  
  <pre><code>print(data[:,[3,5,8]])
  (1, 0) 1
  </code></pre>
  
  <p>But I expected to get, </p>
  
  <pre><code>(1, 3)    1
  (3, 8)    0
  </code></pre>
  
  <p>Similarly I want to get specific rows, but data[list:] does not give desired output. How can I solve this?</p>