title: only integers, slices (`:`), ellipsis (`...`), numpy.newaxis (`None`) and integer or boolean arrays are valid indices, when trying to drop columns
body: <p>I am trying to drop some columns but I wanted to set a variable which numbers the columns I would like to drop instead of hard-coding it.</p>
  <p>My Code is:</p>
  <pre><code>import pandas as pd
  import numpy as np
  
  df = pd.read_csv(WorkdayExcelPathName,low_memory=(False))
  
  ColumnsToDrop = df.iloc[:, [57,125]]
  
  df2 = df.drop(df.columns[ColumnsToDrop], axis = 1)
  
  print(df2)
  </code></pre>
  <p>which gives me this error:</p>
  <blockquote>
  <p>IndexError: only integers, slices (<code>:</code>), ellipsis (<code>...</code>),
  numpy.newaxis (<code>None</code>) and integer or boolean arrays are valid indices</p>
  </blockquote>
  <p>I have also tried using:</p>
  <pre><code>ColumnsToDrop = df.iloc[:, np.r_[57,125]]
  </code></pre>
  <p>But it continues to produce the same <strong>IndexError</strong> error.</p>
  <p>what am I doing wrong?</p>