title: How do I get substring to work in matlab?
body: <p>I apologize if this is a newb question, but I have read the documentation <a href="http://www.mathworks.com/help/symbolic/mupad_ref/substring.html" rel="noreferrer">here</a> and it says nothing about having to input any command before using substring.</p>
  
  <p>However, when I try to call it as follows:</p>
  
  <blockquote>
    <p>substring('hello world', 2)</p>
  </blockquote>
  
  <p>It gives me the error</p>
  
  <blockquote>
    <p>??? Undefined function or method 'substring' for input arguments of type 'char'.</p>
  </blockquote>
  
  <p>What is the correct way to invoke this <code>substring</code>?</p>