title: Why did 'reset_index(drop=True)' function unwantedly remove column?
body: <p>I have a Pandas dataframe named <strong>data_match</strong>. It contains columns '_worker_id', '_unit_id', and 'caption'. (Please see attached screenshot for some of the rows in this dataframe)</p>
  <p><a href="https://i.stack.imgur.com/fm0KK.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/fm0KK.jpg" alt="enter image description here" /></a></p>
  <p>Let's say the index column is not in ascending order (I want the index to be 0, 1, 2, 3, 4...n) and I want it to be in ascending order. So I ran the following function attempting to reset the index column:</p>
  <pre><code>data_match=data_match.reset_index(drop=True)
  </code></pre>
  <p>I was able to get the function to return the correct output in my computer using Python 3.6. However, when my coworker ran that function in his computer using Python 3.6, the '_worker_id' column got removed.</p>
  <p>Is this due to the <code>(drop=True)</code> clause next to <code>reset_index</code>? But I didn't know why it worked in my computer and not in my coworker's computer. Can anybody advise?</p>