title: mutate_each / summarise_each in dplyr: how do I select certain columns and give new names to mutated columns?
body: <p>I'm a bit confused about the <code>dplyr</code> verb <code>mutate_each.</code></p>
  
  <p>It's pretty straightforward to use the basic <code>mutate</code> to transform a column of data into, say, z-scores, and create a new column in your data.frame (here with the name <code>z_score_data</code>):</p>
  
  <pre><code>newDF &lt;- DF %&gt;%
    select(one_column) %&gt;%
    mutate(z_score_data = one_column - (mean(one_column) / sd(one_column))
  </code></pre>
  
  <p>However, since I have many columns of data I'd like to transform, it appears I should probably use the <code>mutate_each</code> verb.</p>
  
  <pre><code>newDF &lt;- DF %&gt;%
       mutate_each(funs(scale))
  </code></pre>
  
  <p>So far so good. But as of yet I haven't been able to figure out:</p>
  
  <ol>
  <li>How can I give these new columns appropriate names, like I can in <code>mutate</code>?</li>
  <li>How can I select certain columns that I wish to mutate, like I did with <code>select</code> in the first case?</li>
  </ol>
  
  <p>Thanks for your help.</p>