title: Make a pie in matplotlib from a column
body: <p>I have a <code>df</code> that has many columns. I need to make a pie using the <code>users</code> columns and appear according to the <code>number</code> column.</p>
  
  <pre><code>users  number   col1  col2
  user1   1        12    abc
  user2   34       13    ..
  user3   56       12
  user4   45       ..
  user5   4
  user1   3
  user5   11
  user1   3
  </code></pre>
  
  <p>How to do the pie according to the percent that users have in the number column?So it can be clear who has the higher number as a percentage of the whole. If you need clarification ask me. Thanks</p>
  
  <p>I did:</p>
  
  <pre><code>plt.pie(x['users'],x['number'])
  </code></pre>
  
  <p>but it says:</p>
  
  <pre><code>ValueError: could not convert string to float: 'user11'
  </code></pre>