title: How to normalize dataframe by standard deviation using scikit-learn?
body: <p>Given the following dataframe and <code>left-x</code> column:</p>
  
  <pre><code>|       | left-x | left-y | right-x | right-y |
  |-------|--------|--------|---------|---------|
  | frame |        |        |         |         |
  | 0     | 149    | 181    | 170     | 175     |
  | 1     | 149    | 181    | 170     | 175     |
  | 2     | 149    | 181    | 170     | 175     |
  | 3     | 149    | 181    | 170     | 175     |
  </code></pre>
  
  <p>how may I normalize <code>left-x</code> by standard deviation using <a href="http://scikit-learn.org" rel="nofollow noreferrer">scikit-learn library</a>?</p>