In cocoa sdk, this is usually the case: if you want to have a date and have a string, look in the Date class for the create method that accepts the string.
[ NSDateFormatter dateFromString: myString]
dateFromString:
Returns a date representation. This string is interpreted using the current receiver settings.
(NSDate *) dateFromString: (NSString *) string
, , NSString Static, stringFromDate ( , , ). , NSDateFormatter , .