title: Why use pandas qcut return ValueError: Bin edges must be unique?
body: <p>I have dataset :</p>
  
  <pre><code>recency;frequency;monetary
  21;156;41879955
  13;88;16850284
  8;74;79150488
  2;74;26733719
  9;55;16162365
  ...;...;...
  </code></pre>
  
  <p>detail raw data -> <a href="http://pastebin.com/beiEeS80" rel="nofollow noreferrer">http://pastebin.com/beiEeS80</a>
  and i put into <code>DataFrame</code> and here is my complete code :</p>
  
  <pre><code>df = pd.DataFrame(datas, columns=['userid', 'recency', 'frequency', 'monetary'])
  df['recency'] = df['recency'].astype(float)
  df['frequency'] = df['frequency'].astype(float)
  df['monetary'] = df['monetary'].astype(float)
  
  df['recency'] = pd.qcut(df['recency'].values, 5).codes + 1
  df['frequency'] = pd.qcut(df['frequency'].values, 5).codes + 1
  df['monetary'] = pd.qcut(df['monetary'].values, 5).codes + 1
  </code></pre>
  
  <p>but it's return error </p>
  
  <pre><code>df['frequency'] = pd.qcut(df['frequency'].values, 5).codes + 1
  ValueError: Bin edges must be unique: array([   1.,    1.,    2.,    4.,    9.,  156.])
  </code></pre>
  
  <p>How to solve this ?</p>