title: How to convert a matrix and save to a csv file
body: <p>I have some data (1003 rows, 4 columns) in format as seen below, and I want to save them in a csv file:</p>
  <p><strong>Current format:</strong></p>
  <pre><code>[['likes_count', 'context', 'category', 'object'], ['1', 1, 0, 4], ['0', 1, 0, 4], ['1', 1, 1, 4], ['1', 1, 0, 4], ['1', 0, 0, 4], ['1', 1, 1, 4], ['1', 1, 1, 4], ['1', 1, 1, 4], ['1', 1, 1, 1], ['1', 1, 1, 1], ['1', 0, 0, 4], ['1', 0, 0, 4], ['1', 0, 1, 4], ['1', 0, 0, 4], ['1', 0, 0, 4], ['1', 0, 1, 1], ['1', 1, 2, 4], ['1', 0, 1, 4], ['1', 0, 1, 4], ['1', 0, 1, 4], ['1', 0, 0, 4], ['1', 0, 2, 1], ['1', 0, 0, 4], ['1', 0, 2, 1], ['1', 1, 2, 1], ['1', 1, 2, 1], ['1', 0, 1, 4], ['1', 0, 1, 4], ['13', 0, 1, 4], ['1', 0, 1, 4], ['2', 1, 2, 4], ['1', 1, 2, 4], [...] etc
  </code></pre>
  <p><strong>Desirable CSV fromat:</strong></p>
  <pre><code>'likes_count', 'context', 'category', 'object'
  ['1', 1, 0, 4] 
  ['1', 1, 0, 4]
  ['1', 1, 1, 4]
  ['1', 1, 0, 4]
  ['1', 0, 0, 4] 
  </code></pre>