title: How to empty a list in Tcl?
body: <p>How do you empty a list in Tcl efficiently?</p>
  
  <p>I have tried using lreplace to empty a list, for example:  </p>
  
  <pre><code>set lst "a b c d e"  
  lreplace $lst 0 [[llength $lst] - 1]  # replace all content in the list with "".
  </code></pre>