title: Finding in a std map using regex
body: <p>I want to know how I can look up for an item in a map using a regex function. In my case, I have a <strong>map</strong> with expressions such as en*, es*, en-AU and so on and I have a <strong>string</strong> of possible values like en, en-US, en-GB, es-CL and so on.</p>
  
  <p>I want to search using that <strong>string</strong> to find that item in the <strong>map</strong>.
  Looking for the key without the wildcard first then looking for the key with the wildcard as the 2nd priority.</p>
  
  <p>Please help me out with this problem or if this is an inefficient or if any one has a different approach please tell me another method for that. I use C++ with boost and stl. </p>