Multidimensional array issues - iphone

Question

I am creating a multidimensional array for sections / rows based on json data from our API. Looking at the logs the adding rows and sections look good but when I nslog the sections it only shows a bunch of the last object. It seems like the rows are not being added to sections.
What am I doing wrong to make the last API object show in the sections x times? x represents the json count. self.appointments is an NSArray *
According to objective-c multi-dimensional array it should work.
NSDictionary *json = [NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:&error];
NSMutableArray *sections = [[NSMutableArray alloc] init];
NSMutableArray *rows = [[NSMutableArray alloc] init];
NSString *lastDate = nil;
for (NSDictionary *dict in [json objectForKey:#"data"]) {
NSString *date = [dict objectForKey:#"date"];
NSLog(#"Dates: %# - %#", date, lastDate);
if (date != lastDate) {
if (lastDate == nil) {
NSLog(#"Adding Row 1");
[rows addObject:dict];
lastDate = date;
} else {
NSLog(#"Adding Section 1");
NSLog(#"Adding #rows %i",[rows count]);
[sections addObject:rows];
[rows removeAllObjects];
NSLog(#"Adding Row 2 %#",[dict objectForKey:#"start_time"]);
[rows addObject:dict];
lastDate = date;
}
} else {
NSLog(#"Adding Row 3");
[rows addObject:dict];
}
}
if (rows) {
NSLog(#"Adding Section 2");
NSLog(#"Adding #rows %i",[rows count]);
[sections addObject:rows];
}
NSLog(#"Sections: %#", sections);
self.appointments = [sections mutableCopy]; //I have also tried self.appointments = sections
sections = nil;
rows = nil;
Logs show
Sections: (
(
{
abbrev = "";
account = "";
"addOnService_id" = "";
alert = "";
"appt_id" = 1839384;
"appt_id_unique" = 1839384;
"appt_status_description" = "";
"appt_status_type" = "";
"c_id" = 47;
cost = "0.00";
"coupon_id" = "";
"creation_emp_id" = 2288;
"creation_timestamp" = 201111040717;
"customer_id" = 0;
"customer_notes" = "";
"customer_package_id" = "";
date = 20121228;
"employee_id" = 2288;
"employee_notes" = "";
employer = "";
"end_time" = 570;
"first_name" = "";
"history_id" = 1830959;
key = 134;
"last_emp_id" = 2288;
"last_name" = "";
"last_timestamp" = 201111040717;
"lead_description" = "";
"link_id" = 0;
"location_name" = "Telephonic Setup/Training";
"make_id" = "";
"middle_name" = "";
"model_id" = "";
"model_year" = "";
name = "My Name ";
odometer = "";
"other_vehicle" = "";
"package_name" = "";
"payment_type_description" = "";
"payment_type_id" = "";
"pet_id" = "";
"po_number" = "";
reason = "B.O.B";
"rebook_id" = "";
"recur_id" = 20954;
"rep_id" = "";
"room_id" = 0;
"room_name" = "";
service = "";
"service_id" = 0;
"service_time_description" = "";
spots = 1;
"staff_screen_name" = "John Smith";
"staff_type_id" = 0;
"start_time" = 540;
"status_id" = 0;
tip = "";
"type_id" = 8;
vin = "";
}
),
(
{
abbrev = "";
account = "";
"addOnService_id" = "";
alert = "";
"appt_id" = 1839384;
"appt_id_unique" = 1839384;
"appt_status_description" = "";
"appt_status_type" = "";
"c_id" = 47;
cost = "0.00";
"coupon_id" = "";
"creation_emp_id" = 2288;
"creation_timestamp" = 201111040717;
"customer_id" = 0;
"customer_notes" = "";
"customer_package_id" = "";
date = 20121228;
"employee_id" = 2288;
"employee_notes" = "";
employer = "";
"end_time" = 570;
"first_name" = "";
"history_id" = 1830959;
key = 134;
"last_emp_id" = 2288;
"last_name" = "";
"last_timestamp" = 201111040717;
"lead_description" = "";
"link_id" = 0;
"location_name" = "Telephonic Setup/Training";
"make_id" = "";
"middle_name" = "";
"model_id" = "";
"model_year" = "";
name = "My Name ";
odometer = "";
"other_vehicle" = "";
"package_name" = "";
"payment_type_description" = "";
"payment_type_id" = "";
"pet_id" = "";
"po_number" = "";
reason = "B.O.B";
"rebook_id" = "";
"recur_id" = 20954;
"rep_id" = "";
"room_id" = 0;
"room_name" = "";
service = "";
"service_id" = 0;
"service_time_description" = "";
spots = 1;
"staff_screen_name" = "John Smith";
"staff_type_id" = 0;
"start_time" = 540;
"status_id" = 0;
tip = "";
"type_id" = 8;
vin = "";
}
), ... over and over again.

Answer 1

With:
[sections addObject:rows];
[rows removeAllObjects];
[rows addObject:dict];
you keep adding the same rows object not a new one and keep changing the contents so the last contents display each time.
Try:
[sections addObject:[rows mutableCopy]];
[rows removeAllObjects];
[rows addObject:dict];
That way a new row is added each time.
Perhaps better yet:
NSDictionary *json = [NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:&error];
NSMutableArray *sections = [NSMutableArray array];
NSMutableArray *rows = [NSMutableArray array];
NSString *lastDate = nil;
for (NSDictionary *dict in [json objectForKey:#"data"]) {
NSString *date = [dict objectForKey:#"date"];
if ([date isEqualToString:lastDate] == NO) {
if (lastDate == nil) {
[rows addObject:dict];
lastDate = date;
} else {
[sections addObject:rows];
rows = [NSMutableArray array];
[rows addObject:dict];
lastDate = date;
}
[rows addObject:dict];
}
}
if (rows) {
[sections addObject:rows];
}
self.appointments = sections;
Note that assigning 0 to an object does not release it, release does. But if you use convenience methods to create objects then they are autoreleased and no further action is necessary to release them.
Also note that when comparing strings one needs to use the isEqualToString: method to compare the contents, just using the = or != only compares the address of the strings.