title: Stemming process not working in Python
body: <p>I have a text file that I am trying to <code>stem</code> after having removed <code>stopwords</code> but it seems that nothing changes when I run it. My file is called <code>data0</code>. </p>
  
  <p>Here are my codes:</p>
  
  <pre><code>## Removing stopwords and tokenizing by words (split each word)
  from nltk.corpus import stopwords
  from nltk.tokenize import word_tokenize
  
  data0 = word_tokenize(data0)
  data0 = ' '.join([word for word in data0 if word not in (stopwords.words('english'))])
  print(data0)
  
  ## Stemming the data
  from nltk.stem import PorterStemmer
  
  ps = PorterStemmer()
  data0 = ps.stem(data0)
  print(data0)
  </code></pre>
  
  <p>And I get the following (wrapped for legibility):</p>
  
  <blockquote>
    <p>For us around Aberdeen , question `` What oil industry ? ( Evening Express , October 26 ) touch deja vu . That question asked almost since day first drop oil pumped North Sea . In past 30 years seen constant cycle ups downs , booms busts industry . I predict happen next . There period worry uncertainty scrabble find something keep local economy buoyant oil gone . Then upturn see jobs investment oil , everyone breathe sigh relief quest diversify go back burner . That downfall . Major industries prone collapse . Look nation 's defunct shipyards extinct coal steel industries . That 's vital n't panic downturns , start planning sensibly future . Our civic business leaders need constantly looking something secure prosperity - tourism , technology , bio-science emerging industries . We need economically strong rather waiting see happens oil roller coaster hits buffers . N JonesEllon</p>
  </blockquote>
  
  <p>The first part of the code works fine (Removing stopwords and tokenizing), but us the second part (Stem) which does not work. Any idea why?</p>