title: Join a string from name/value data in a different order in JSON
body: <p>Here are two examples of the format of JSON data I am loading:</p>
  
  <pre><code>"address": {
      "locality": "London",
      "postal_code": "L1 1RE",
      "region": "London",
      "address_line_1": "1 Tower Road"
    },
    "date_of_creation": "2013-01-02",
     ....
  
  "address": {
      "postal_code": "KY7 6SD",
      "address_line_2": "A Business Park",
      "address_line_1": "Headquarters",
      "locality": "Fife",
      "region": "Glenrothes"
    },
    "date_of_creation": "2010-02-01",
  </code></pre>
  
  <p>I would like to return a string that joins the address object in a specific order which is out of sequence of the JSON data. i.e </p>
  
  <pre><code>str = address['address_line_1'] + ',' + address['address_line_2'] + ',' 
  + address['locality'] + ',' + address['region'] + ',' + 
  address['postal_code']
  </code></pre>
  
  <p>However not every address object contains all they keys, the order isn't always the same and in the first example, I don't want to join the values if they are the same (locality and region).</p>
  
  <p>What is the best way to create this string?</p>