Question

well i am storing An id of a student into a NSMUtableArray what i am trying is that to expand that array to accept two field rather than just the student id

[[NSUserDefaults standardUserDefaults] synchronize];
NSArray *archivedArray = [NSKeyedUnarchiver unarchiveObjectWithFile:[self dataFilePath]];
if (archivedArray == nil) {

    data = [[NSMutableArray alloc] init];         
} else {
    data = [[NSMutableArray alloc] initWithArray:archivedArray];
}

As you can see the data variable is only expecting one field

Answer 1

If I understand your question correctly, you want to have two (or more, later) fields for each “record” in the array.

One common way to do that could be to create a dictionary with the fields you need, then add the dictionaries to the array:

NSDictionary *student1 = [NSDictionary dictionaryWithObjectsAndKeys:
                          @"key1", @"id",
                          @"Joe", @"name",
                          nil];

NSMutableArray *array = [NSMutableArray arrayWithObjects:student1, nil];

Feel free to add more fields to the student record, and more students to the array. The id field of the dictionary maybe shouldn’t be a string, either, but that’ll do for a start.