title: Python Pandas: drop a column from a multi-level column index?
body: <p>I have a multi level column table like this:</p>
  
  <pre><code>    a
     ---+---+---
      b | c | f
  --+---+---+---
  0 | 1 | 2 | 7
  1 | 3 | 4 | 9
  </code></pre>
  
  <p>How can I drop column "c" by name? to look like this:</p>
  
  <pre><code>    a
     ---+---
      b | f
  --+---+---
  0 | 1 | 7
  1 | 3 | 9
  </code></pre>
  
  <p>I tried this:</p>
  
  <pre><code>del df['c']
  </code></pre>
  
  <p>but I get the following error, which makes sense:</p>
  
  <blockquote>
    <p>KeyError: 'Key length (1) was greater than MultiIndex lexsort depth (0)'</p>
  </blockquote>