One of the most important tasks that a developer has to deal with when creating applications is the data handing and manipulation. Data can be expressed in many different formats, and mastering at least the most known of them consists of a key ability for every single programmer. Speaking for mobile applications specifically now, it’s quite common nowadays for them to exchange data with web applications. In such cases, the way that data is expressed may vary, but usually is preferred either the JSON or the XML format.
iOS SDK provides classes for handling both of them. For managing JSON data, there is the NSJSONSerialization class. This one allows to easily convert a JSON data into a Foundation object (NSArray, NSDictionary), and the other way round. For parsing XML data, iOS offers the NSXMLParser class, which takes charge of doing all the hard work, and through some useful delegate methods gives us the tools we need for handling each step of the parsing.