Why does json values get sorted alphabetically iOS?

Question

Possible Duplicate:
JSONkit sorting issues

I have the following jSON

[
  {
    "Pending": 67,
    "Past Due": 63,
    "Invites": 0
  },
  {
    "Reading Approval": 4,
    "Schedule Approval": 16,
    "Session Assignment": 1
  },
  {
    "Reading Approval": 3,
    "Schedule Approval": 20,
    "Class Approval": 20,
    "Module Approval": 2,
    "Training Plan Review": 2,
    "Job Confirmation": 1
  }

]

When I assign the json string to a nsarray the values inside the dictionary gets sorted alphabetically.

NSArray *arr = [strResult JSONValue];

How can I keep the same order as the json string?

arr = 
{
  Invites = 0;
  "Past Due" = 63;
  Pending = 67;
},
{
  "Reading Approval" = 4;
  "Schedule Approval" = 16;
  "Session Assignment" = 1;
},
{
  "Class Approval" = 20;
  "Job Confirmation" = 1;
  "Module Approval" = 2;
  "Reading Approval" = 3;
  "Schedule Approval" = 20;
  "Training Plan Review" = 2;
}
)

This is the table I want to display:

Group 1
  Pending    67
  Past Due   63
  Invites    0

Group 2
  Reading Approval    4
  Schedule Approval   16
  Session Assignment  1

Group 3
  Reading Approval      3
  Schedule Approval     20
  Class Approval        20
  Module Approval       2
  Training Plan Review  2
  Job Confirmation      1

I'm using this json to display the data in a grouped UITableView and I need it to be in the order that it comes from the database, how can I approach what I need? — Angie, May 29 '12 at 13:51

Jeffery Thomas · Accepted Answer · 2012-05-29T15:44:11.590

Using standard JSON parsers, you will need to change your data.

[
  [
    { "Pending": 67 },
    { "Past Due": 63 },
    { "Invites": 0 }
  ],
  [
    { "Reading Approval": 4 },
    { "Schedule Approval": 16 },
    { "Session Assignment": 1 }
  ],
  [
    { "Reading Approval": 3 },
    { "Schedule Approval": 20 },
    { "Class Approval": 20 },
    { "Module Approval": 2 },
    { "Training Plan Review": 2 },
    { "Job Confirmation": 1 }
  ]
]

Assuming it's possible for you to change your JSON format.

How to access the data. Assuming you have the array of sections and know the section and row indexes.

NSArray *sections = ...
NSUInteger sectionIndex = ...
NSUInteger rowIndex = ...

NSArray *rows = [sections objectAtIndex:sectionIndex];
NSDictionary *cell = [rows objectAtIndex:rowIndex];

NSString *name = [[cell allKeys] objectAtIndex:0];
NSNumber *value = [cell objectForKey:name];

// What ever you need to do

If you want to iterate over all the data

NSArray *sections = ...

for (NSArray *rows in sections) {
    for (NSDictionary *cell in rows) {
        NSString *name = [[cell allKeys] objectAtIndex:0];
        NSNumber *value = [cell objectForKey:name];

        // What ever you need to do
    }
}

Yes I can change the JSON format. How will I read it? I updated in my question the table table I want to display with the data. — Angie, May 29 '12 at 15:06
I changed the JSON format and read the data as you mentioned above and it worked really great. Thank you for the help. — Angie, May 29 '12 at 17:51

score 1 · Answer 2 · answered May 29 '12 at 15:21

A NSDictionary is an unordered container object. If it gets printed, it is sorted alphabetically. But there is no guaranteed order.

Documentation of description: says:

If each key in the dictionary is an NSString object, the entries are listed in ascending order by key, otherwise the order in which the entries are listed is undefined. [...]

allKeys:says:

The order of the elements in the array is not defined.

and allValuesalso says:

The order of the elements in the array is not defined.

BUT a NSArray is an ordered container. That's why Jeffery Thomas statet, that you should use Arrays for each JSON Entry.

But you could also try to use smth like:

[
  [
    "keys": {"Pending","Past Due","Invites"},
    "values": {67,63,0}
  ],
  [
    "keys": {"Reading Approval","Schedule Approval","Session Assignment"},
    "values": {4,16,1},
  ],
  [
    "keys": {"Reading Approval","Schedule Approval","Class Approval",...},
    "values": {3,20,20,...},
  ]
]

This also looks like it will work and thank you too for your help. — Angie, May 29 '12 at 17:52

score 0 · Answer 3 · answered May 29 '12 at 15:14

0

Dictionary does not have its items ordered. The sorting is done by iOS only to display it nicely. However, you should never assume any ordering of items in a dictionary.

answered May 29 '12 at 15:14

Sulthan

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Why does json values get sorted alphabetically iOS?

3 Answers3