title: How to convert string to camel case with non alphanumeric characters?
body: <p>I need to convert a string to camel case, it's easy by using:</p>
  
  <pre><code>mb_convert_case($str, MB_CASE_TITLE, "UTF-8")
  </code></pre>
  
  <p>But what if string contains non-alphanumeric characters:</p>
  
  <pre><code>$str = 'he said "hello world"';
  echo mb_convert_case($str, MB_CASE_TITLE, "UTF-8");
  </code></pre>
  
  <p>Result is:</p>
  
  <pre><code>He Said "hello World"
  </code></pre>
  
  <p>But I need:</p>
  
  <pre><code>He Said "Hello World"
  </code></pre>
  
  <p>How can we handle this?</p>
  
  <p>tHanks</p>