title: how to delete variables in matlab command window?
body: <p>I want to delete some variables that I have declared in command window in matlab, I tried clear all but it didn't work. I typed the following in the command window,
  e.g. </p>
  
  <pre><code>a = 10;
  str = 'a';
  clear all
  </code></pre>
  
  <p>Matlab doesn't delete them, why?
  Is there any function that can do this for me?</p>