title: How to remove numbers in a string in Tcl using regsub?
body: <p>I would like to remove the numbers in a string but wish to remain the words that contain numbers. For example:</p>
  
  <pre><code>set a "t0day 1s a 234 5unny d4y 123"
  </code></pre>
  
  <p>The expected output:</p>
  
  <pre><code>t0day 1s a 5unny d4y
  </code></pre>
  
  <p>I have tried as below, but it is not working:</p>
  
  <pre><code>regsub -all {[^0-9]} $a " " a
  </code></pre>