How to store parsed date value as date format in mutable array as mutable dictionary in iphone?

I am new to iphone deve开发者_如何学运维lopment .I have parsed a xml page and stored the title, date, summary, in a mutable array "stories" as mutable dictionary "object for key".All the values are saved as string But i want to save the Date value as date format.So that i can sort it with date.How can i achieve that.Please help me out.Thanks

1. Create an instance of NSDateFormatter.
2. Configure the date formatter so that it understands the format you want it to parse (setDateFormat:, setTimeFormat:).
3. Call the date formatter's -dateFromString: method.