title: Remove first occurrence of underscore in a string
body: <p>I have a character string of names which look like </p>
  
  <pre><code>"_6302_I-PAL_SPSY_000237_001"
  </code></pre>
  
  <p>I need to remove the first occurred underscore, so that it will be as</p>
  
  <pre><code>"6302_I-PAL_SPSY_000237_001"
  </code></pre>
  
  <p>I aware of <code>gsub</code> but it removes all of underscores. Thank you for any suggestions.</p>