title: How to mathematically evaluate a string like "2-1" to produce "1"?
body: <p>I was just wondering if PHP has a function that can take a string like <code>2-1</code> and produce the arithmetic result of it?</p>
  
  <p>Or will I have to do this manually with <code>explode()</code> to get the values left and right of the arithmetic operator?</p>