title: How to escape a question mark in R?
body: <p>I am trying to grep a vector of strings and some of them contain question marks.</p>
  
  <p>I am doing:</p>
  
  <p><code>grep('\?',vectorofStrings)</code>
  and getting this error:</p>
  
  <p><code>Error: '\?' is an unrecognized escape in character string starting "\?"</code></p>
  
  <p>How can I determine the proper escaping procedure for '?'</p>