title: Python: Find a list of words in a text and return its index
body: <p>I have to process a document in plain text, looking for a word list and returning a text window around each word found. I'm using <a href="http://nltk.org/" rel="nofollow">NLTK</a>.</p>
  
  <p>I found posts on Stack Overflow where they use regular expressions for finding words, but without getting their index, just printing them. I don't think use RE is right, cause I have to find specific words.</p>