title: Selecting data frame rows based on partial string match in a column
body: <p>I want to select rows from a data frame based on partial match of a string in a column, e.g. column 'x' contains the string &quot;hsa&quot;. Using <code>sqldf</code> - <em>if</em> it had a <code>like</code> syntax - I would do something like:</p>
  <p><code>select * from &lt;&gt; where x like 'hsa'</code>.</p>
  <p>Unfortunately, <code>sqldf</code> does not support that syntax.</p>
  <p>Or similarly:</p>
  <pre><code>selectedRows &lt;- df[ , df$x %like% &quot;hsa-&quot;]
  </code></pre>
  <p>Which of course doesn't work.</p>
  <p>Can somebody please help me with this?</p>