title: Pandas Apply Function Working Very Slowly
body: <p>I'm passing the following function to a pandas column with 3 million comments in order to extract the adjectives. I was expecting it to be done very quickly as it can be done in parallel computation. Though it's taking around 5 hours or so as if it is a for loop. Is there possible any solution to this? Like Cython?</p>
  <pre><code> def get_adjectives(row):
      clean_row=''
      if type(row)==str:
        for word in row.split():
          if nltk.pos_tag([word])[0][1] in ['JJ','JJR','JJS']:
            clean_row=clean_row+word+' '
      return clean_row
  
    df['adjectives'] = df[text_column].apply(get_adjectives)
  </code></pre>