title: Initialising 'double' with an expression of incompatible type 'id'
body: <p>Im trying to assign a value to a double, using the following code:</p>
  
  <pre><code>double distanceFormat = [self.runsArray[indexPath.row] valueForKey:@"runDistance"];
  </code></pre>
  
  <p>But I keep getting the following error:</p>
  
  <pre><code>Initialising 'double' with an expression of incompatible type 'id'
  </code></pre>
  
  <p>However, I know the value is a double! Is there a way to do this?</p>