title: Regex to extract string not included in double quotes
body: <p>E.g., I need to get everything outside double quotes:</p>
  
  <pre><code>This is a string outside quotes, and "these words are in quotes" which I want to ignore.
  </code></pre>
  
  <p>The result should be:</p>
  
  <pre><code>This is a string outside quotes, and  which I want to ignore.
  </code></pre>
  
  <p>After many searches I found very similar one like:
  <a href="http://www.rubular.com/r/kxm0cEx8gD" rel="nofollow">http://www.rubular.com/r/kxm0cEx8gD</a></p>
  
  <p>But it doesn't give me desired result.</p>
  
  <p>What I managed to achieve so far is:</p>
  
  <pre><code>(.?(?!["]))((?&lt;!["]).?)
  
      (.?(?!["])) - negative lookahead - I expect to give me all symbols before the ["]
  
      ((?&lt;!["]).?) - negative lookbehind - I expect to give all the symbols not preceded by ["]
  </code></pre>
  
  <p>I'm using R which supports perl syntax and PCRE 8.0</p>