title: How to remove columns and rows at certain indexes in numpy, at the same time
body: <p>I've such a square matrix:</p>
  <pre><code>[[0, 516, 226, 853, 1008, 1729, 346, 1353, 1554, 827, 226, 853, 1729, 1008],
  [548, 0, 474, 1292, 1442, 2170, 373, 1801, 1989, 1068, 474, 1292, 2170, 1442],
  [428, 466, 0, 1103, 1175, 1998, 226, 1561, 1715, 947, 0, 1103, 1998, 1175],
  [663, 1119, 753, 0, 350, 1063, 901, 681, 814, 1111, 753, 0, 1063, 350],
  [906, 1395, 1003, 292, 0, 822, 1058, 479, 600, 1518, 1003, 292, 822, 0],
  [1488, 1994, 1591, 905, 776, 0, 1746, 603, 405, 1676, 1591, 905, 0, 776],
  [521, 357, 226, 1095, 1167, 1987, 0, 1552, 1705, 1051, 226, 1095, 1987, 1167],
  [1092, 1590, 1191, 609, 485, 627, 1353, 0, 422, 1583, 1191, 609, 627, 485],
  [1334, 1843, 1436, 734, 609, 396, 1562, 421, 0, 1745, 1436, 734, 396, 609],
  [858, 1186, 864, 1042, 1229, 1879, 984, 1525, 1759, 0, 864, 1042, 1879, 1229],
  [428, 466, 0, 1103, 1175, 1998, 226, 1561, 1715, 947, 0, 1103, 1998, 1175],
  [663, 1119, 753, 0, 350, 1063, 901, 681, 814, 1111, 753, 0, 1063, 350],
  [1488, 1994, 1591, 905, 776, 0, 1746, 603, 405, 1676, 1591, 905, 0, 776],
  [906, 1395, 1003, 292, 0, 822, 1058, 479, 600, 1518, 1003, 292, 822, 0]]
  </code></pre>
  <p>And I need to remove say <code>a1</code> <code>a2</code> and <code>a3</code> indexed columns and rows at the sametime. How can I do this? What is the neat way?</p>
  <p>Note that, I need to get another square matrix. Both rows and columns at the same index should be removed. Also note that, when you remove a row/column, indexes get shifted. Either I need to shift e.g. <code>a1</code>, <code>a2</code>, <code>a3</code> too or do something more clever.</p>
  <h2>An example case</h2>
  <p>The square matrix:</p>
  <pre><code>[[10,11,12,13],
   [14,15,16,17],
   [18,19,20,21],
   [22,23,24,25]]
  </code></pre>
  <p>remove 1st and 3rd indexes and the result is:</p>
  <pre><code>[[10,12],
   [18,20]]
  </code></pre>