title: Extract string before "_" or "." characters
body: <p>I want to extract string before "_" or "." characters. 
  e.g..
  My C column can have following values and expected output in E:</p>
  
  <pre><code>C                            E
  115415.csv                115415
  12345_BOI_CEO.csv         12345
  </code></pre>
  
  <p>I have a formula for "_" i.e. </p>
  
  <pre><code>IFERROR(LEFT(C10, FIND("_", C10)-1),"")
  </code></pre>
  
  <p>So I want a formula which would extract string before the character mentioned in a single formula and not separate formula. </p>