title: regexextract isn't working the way I want in Google Sheets
body: <p>...or rather...there's something wrong with my formula.</p>
  
  <p>I have a series of item numbers, and I want to extract <em>only</em> the info between the first and 3rd dash, if any.</p>
  
  <p>The info before the 1st dash <em>must</em> be letters.<br>
  The info between the 1st and second dash <em>must</em> be letters (i.e. A-z).<br>
  The info between the 2nd and 3rd dash <em>must</em> be numbers.<br>
  I want everything else to be ignored (I've wrapped my regexextract in an iferror to do this)</p>
  
  <p>Here's my formula:</p>
  
  <pre><code>=arrayformula(iferror(regexextract(B1:B,"[A-z]+-([A-Z\{\\\]\^_`a-z]+-[0-9]+)-"),"")
  </code></pre>
  
  <p>It's working most of the time.</p>
  
  <p>But for this: AAB-2971-PN-B-11-03<br>
  It extracts this: B-11<br>
  But I'm expecting this one to be an error/blank.</p>
  
  <p>Other <em>correct</em> examples:<br>
  AAB-LL-1234-00  should extract  LL-1234<br>
  AAN-1234  should error out<br>
  AAC-1234-LL  should error out<br>
  AAC-1234-ll-123  should error out<br></p>