title: "'\w' is an unrecognized escape" in grep
body: <p>I'm using grep in some projects in R (which uses a <code>perl=TRUE</code> flag) and for the life of me I can't figure out why R keeps throwing errors. My query is as follows:</p>
  
  <pre><code>d$SomeColumn[grep("(?ix)&lt;VNW[^;]*;(dis|dat)&gt; \w*&lt;N\(", d$Right, perl=TRUE)] &lt;- 1
  </code></pre>
  
  <p>However, R throws the following error:</p>
  
  <pre><code>Error: '\w' is an unrecognized escape in character string starting ""&lt;VNW[^;]*;(dis|dat)&gt; \w"
  </code></pre>