title: how to concatenate (variable + object key names) to get the object values in dot notation
body: <p>Assuming I've a JSON object like this:</p>
  
  <pre><code>var myObj = {
      'question1': {
          'option1': 'foo',
          'option2': 'bar',
          'option3': 'baz'
      },
      'question2': {
          ...
      },
      'question3': {
          ...
      }
  };
  </code></pre>
  
  <p>And since its children always has a number in its keys, I want to do a loop and <strong>concatenate</strong> the loop's index to the object keys, and get the values in the dot notation method... </p>
  
  <p>So, I guess to get the values, I need to do some thing like this:</p>
  
  <pre><code>myObj.'question'+i
  </code></pre>
  
  <p>How can I do the concatenation right?</p>