title: Why do I lose indexes and column header information on using np.hstack when concatenating two df in python?
body: <p>I have two dataframes:
  Reprex:</p>
  
  <p>DF1</p>
  
  <pre><code>X
  Yes
  No
  Maybe
  </code></pre>
  
  <p>DF2</p>
  
  <pre><code>Y
  Yes
  No
  Maybe
  
  import pandas as pd
  import numpy as np
  train = pd.DataFrame(np.hstack([DF1,DF2]))
  </code></pre>
  
  <p>train</p>
  
  <pre><code>0 1
  Yes Yes
  No  No
  Maybe Maybe
  </code></pre>
  
  <p>Why do my headers change from X and Y. the train df should keep my original headers from both df. I tried making axis=1 and headers=true but it did not work. pd.concat is not effective because i end up with more rows than what are in my original df.</p>
  
  <p>I also tried</p>
  
  <pre><code>df.reset_index()
  </code></pre>
  
  <p>but even after that pd.concat gave me more rows than my original two dataframes have. </p>