title: How to get sentence number in spaCy?
body: <p>I get the tokens for a string as</p>
  
  <pre><code>doc = nlp(u"This is the first sentence. This is the second sentence.")
  for token in doc:
      print(token.i, token.text)
  </code></pre>
  
  <p>with the output</p>
  
  <pre><code>0 This
  1 is
  2 the
  3 first
  4 sentence
  5 .
  6 This
  7 is
  8 the
  9 second
  10 sentence
  11 .
  </code></pre>
  
  <p>How can I get the sentence number as <code>(SENTENCE_NUMBER, token.i, token.text)</code></p>
  
  <pre><code>0 0 This
  0 1 is
  0 2 the
  0 3 first
  0 4 sentence
  0 5 .
  1 0 This
  1 1 is
  1 2 the
  1 3 second
  1 4 sentence
  1 5 .
  </code></pre>
  
  <p>I can reset the token number in the loop, but how can I get the sentence number from <code>doc</code>?</p>