title: How to remove a word in LDA analysis by gensim
body: <p>I'm using gensim to do a LDA topic modeling work.
  My data was pretreated by some other people. He gave me two things.
  ①the mmcorpus file(imported by <code>gensim.corpora.MmCorpus</code> function)
  ②the dictionary file(imported by <code>gensim.corpora.Dictionary.load</code> function)
  I created the LDA model successfully and adjusted the superparameter ALPHA from 0.5-1.5 and I drew a visualized chart like this:
  <a href="https://i.stack.imgur.com/zRgHA.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/zRgHA.png" alt="enter image description here"></a>
  I was confused why there are several tall bars there. And I found some strange words like this:
  <a href="https://i.stack.imgur.com/4dTsQ.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/4dTsQ.png" alt="enter image description here"></a>
  Interestingly the letter "b" which I haven't seen before appears. The man who gave me the data said the  letter "b" may generated automatically when he converted the data into bytes type. He doesn't know how to erase the "b"  neither do I. How can I delete the "b" when I just have the mmcorpus file and the dictionary file?
  Please!</p>