title: REGEXMATCH with regex reference to cell
body: <p>I'm filtering numbers on a gSheet by keyword, as selected by viewers from a pre-determined dropdown list created through data validation.</p>
  
  <p>There are multiple options viewers can select, including "All". Because "All" is not a filterable keyword in the data source, I am using FILTER(REGEXMATCH(IF(...))) to sort the data. The dropdown list lives in cell B1, so I'm referencing this within the REGEXMATCH when the IF statement is false.</p>
  
  <p><strong>Issue</strong>: RegEx matches to text, not numbers. When I reference the cell B1, the formula errors out because it's not a text value. But when I make it a text value, it finds no match (of course).</p>
  
  <hr>
  
  <p><strong>Current</strong>:</p>
  
  <pre><code>=SUM(IFERROR(FILTER(Sheet1!$E:$E,
  REGEXMATCH(Sheet1!$I:$I,IF(B1="All","organic|paid|other",B1))=true),0))
  </code></pre>
  
  <ul>
  <li>Column E is summed based on the keyword selected</li>
  <li>Column I contains the keyword(s) to match</li>
  <li>Cell B1 has the dropdown list where users select their keyword</li>
  </ul>
  
  <hr>
  
  <p><strong>What I've tried</strong>:</p>
  
  <ul>
  <li><code>VALUE(B1)</code> - Referencing it as a value, with the hope it would then read the text that is returned; it errored from bad input</li>
  <li><code>TEXT(B1)</code> - Referencing it as text; it read "B1"</li>
  <li><code>"""&amp;B1&amp;"""</code> - Triple quotes, with the idea that the quoted quotes will pass and encase the text returnd by B1; it read "&amp;B1&amp;" (d'oh)</li>
  <li><code>\"B1\"</code> - Escaping the cell reference; my first time trying to escape in regex, so this may very well be the right answer with a bad implementation</li>
  </ul>
  
  <p>Any other ideas to reference cell B1 from within a REGEXMATCH expression?</p>