Maintain order of elements of NSMutableDictionary [duplicate] - ios

Question

This question already has answers here:
Maintaining the order while iterating a NSDictionary
(3 answers)
Closed 3 years ago.
I am getting a dictionary of the following format :
[
{
"position": "1",
"name": "Jaen",
"group": "Student",
"Address": "Delhi"
},
{
"position": "2",
"name": "Jaen",
"group": "Student",
"Address": "Delhi"
},
{
"position": "1",
"name": "Jaen",
"group": "Teacher",
"Address": "Delhi"
}
]
Basically, I want to group them around the key named "group".I have to create a dictionary in the following format to populate data in my UI.
[
{
"Student": [
{
"position": "1",
"name": "Jaen",
"group": "Student",
"Address": "Delhi"
},
{
"position": "2",
"name": "Jaen",
"group": "Student",
"Address": "Delhi"
}
],
"Teacher": [
{
"position": "1",
"name": "Jaen",
"group": "Teacher",
"Address": "Delhi"
}
]
}
]
the order of the Groups should be maintained ie Student should come before Teacher. But when I am printing dictGroupField it is giving random results in terms of order.
How can i maintain the order?
Please find the code below that I was using :
#property (strong, nonatomic) NSMutableDictionary *dictGroupField;
-(void)loadFieldData {
_dictGroupField = [[NSMutableDictionary alloc] init];
NSMutableArray *arrayFields = [self getArrayFields];
for (NSDictionary *dictT in arrayFields) {
NSString *strGroup = [dict valueForKey:#"group"];
if ([_dictGroupField valueForKey:strGroup] == nil) {
NSMutableArray *arrGroup = [[NSMutableArray alloc] init];
[arrGroup addObject:dict];
[_dictGroupField setObject:arrGroup forKey:strGroup];
} else {
NSMutableArray *arrGroupExist = [_dictGroupField valueForKey:strGroup];
[arrGroupExist addObject:dict];
[_dictGroupField setObject:arrGroupExist forKey:strGroup];
}
}
}

Answer 1

You can't maintain it order. Dictionaries are unordered collections of key-value associations. See more Docs