title: RegEx : Find match based on 1st two chars
body: <p>I am new to RegEx and thus have a question on RegEx. I am writing my code in C# and need to come up with a regex to find matching strings.</p>
  
  <p>The possible combination of strings i get are,</p>
  
  <pre><code>XYZF44DT508755
  ABZF44DT508755
  PQZF44DT508755
  </code></pre>
  
  <p>So what i need to check is whether the string starts with XY or AB or PQ.</p>
  
  <p>I came up with this one and it doesn't work.</p>
  
  <pre><code>^((XY|AB|PQ).){2}
  </code></pre>
  
  <p><strong>Note: I don't want to use regular string StartsWith()</strong></p>
  
  <p><strong>UPDATE:</strong></p>
  
  <p>Now if i want to try a new matching condition like this - </p>
  
  <pre><code>If string starts with "XY" or "AB" or "PQ" and 3rd character is "Z" and 4th character is "F"
  </code></pre>
  
  <p>How to write the RegEx for that?</p>