title: AttributeError - 'numpy.ndarray' object has no attribute 'drop'
body: <p>For a current project, I am planning to run a scikit-learn Stochastic Graduent Booster algorithm over a CSV set that includes numerical data.</p>
  <p>When calling <code>X = Germany.drop('Status', axis='columns')</code> of the script, I am however receiving an <code>AttributeError: 'numpy.ndarray' object has no attribute 'drop'</code>.</p>
  <p>I assume that this error could be related to the fact that I am converting the CSV data <code>pd.to_numeric</code>, which possibly also converts the string headers. Is there any smart tweak that can make this run?</p>
  <p>The CSV data has the following structure:</p>
  <p><a href="https://i.stack.imgur.com/uRgWY.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/uRgWY.png" alt="enter image description here" /></a></p>
  <p>And the corresponding code looks like this:</p>
  <pre><code>Germany = pd.read_csv('./Germany_filtered.csv', index_col=0)
  Germany = Germany.fillna(&quot;&quot;)
  Germany = pd.to_numeric(Germany.columns.str, errors='coerce')
  Germany.head()
  
  X = Germany.drop('Status', axis='columns')
  y = Germany['Status']
  </code></pre>