title: Julia DataFrame multiple values filtering
body: <p>There are two ways to filter DataFrame in case below:</p>
  
  <pre><code>1. df = df[((df[:field].==1) | (df[:field].==2)), :]
  2. df = df[[in(v, [1, 2]) for v in df[:field]], :]
  </code></pre>
  
  <p>Second approach is slower but it's suitable for mutable set of values in condition.
  Is there any syntactic sugar I missed so I can get it as fast as 1st way but with some <code>in</code>-like construction?</p>