title: string.format syntax in c# and what it does?
body: <p>I am currently trying to modify a script for a SSIS project to import data from a dynamic .txt file (sometimes colums are added).</p>
  
  <p>I am new to c# and the only problem in the script is that it contains a string format expression that I really can't graps so my question is:</p>
  
  <p>What does this do?</p>
  
  <pre><code>string _Statement = String.Format ("{0}(?=(?:[^{1}]*{1}[^{1}]*{1})*(?![^{1}]*{1}))"
  </code></pre>
  
  <p>The parameters are </p>
  
  <pre><code>  {0} = First line in the file containing all the column headers
    {1} = Semicolon delimiter
  </code></pre>
  
  <p>Any help in this would be much appreciated.</p>