Array of array Objective-C

Question

I have 4 NSArray in which each object is dictionary. Something like this:

**Array1 - 30 objects(dictionaries):**

[0]
<Key>Name</key> - <Value>Paul</value>
<Key>City</key> - <Value>New York</value>
<key>Birthday</key> - <value>5.4.1954</value>

[1]
<Key>Name</key> - <Value>John</value>
<Key>City</key> - <Value>New York</value>
<key>Birthday</key> - <value>1.17.1936</value>
etc.

**Array2 - 40 objects(dictionaries):**

[0]
<Key>Name</key> - <Value>Queen</value>
<key>Birthday</key> - <value>5.4.1970</value>

[1]
<Key>Name</key> - <Value>TennesseeKids</value>
<key>Birthday</key> - <value>1.17.1995</value>

etc.

All arrays have the key "birthday".

I Want: combine all the array in one big NSMutableArray/NSMutableDictionary and retrieve first 10 records ordered by date.

I don't ask you how to order my record by date or something, I just want to know what is the best way to implement my idea.

I tried to add all arrays in NSMutableDictionary:

[_mainDictionary setObject:array1 for key:@"firstarray"];
[_mainDictionary setObject:array2 for key:@"secondarray"];
[_mainDictionary setObject:array3 for key:@"thirdarray"];
[_mainDictionary setObject:array4 for key:@"fourarray"];

But I don't think that this is the best way to do it.

Hope for your help. Cheers.

In order to retrieve the values by date, you need to timestamp them. When you add a new `NSDictionary` object to the array, it should have a `"date"` key with the current date set to be its value. — 67cherries, Feb 11 '14 at 14:32
Do you really need dictionaries ? I think a better approach is to use simple `Data Objects` and combine those in one array. Then you can filter them with `NSPredicate` — matthisb, Feb 11 '14 at 14:39
In this big array i want to know the name of the array for each record. For example i need to know that Paul from New York and date 5.9.1954 is from array1 and TennesseeKids is from array2 — Bobby Redjeans, Feb 11 '14 at 14:52

score 2 · Accepted Answer · answered Feb 11 '14 at 14:32

2

You want to combine a number of arrays into a single array. Create an NSMutableArray and call addObjectsFromArray: repeatedly, each time with one of the other arrays as the argument. Now you have one array of dictionaries that you can sort / filter.

Your current code adds the arrays to a dictionary which won't offer you any support with sorting / filtering.

answered Feb 11 '14 at 14:32

Wain

118,658
15
128
151

Sorry, but i forgot to say something. I want to know the name of the array for each record (array1 or array2,3,4)... – Bobby Redjeans Feb 11 '14 at 14:48
Are the array contents unique? You could use `contains:` after you have sorted, filtered and selected an item. Or, better, add a key/value pair to the dictionaries to say where they originate from. You may be better off asking about your source data and your requirement from a user point of view. How did you get to multiple different arrays? – Wain Feb 11 '14 at 14:52
elf.array1=[NSJSONSerialization JSONObjectWithData:response options:NSJSONReadingMutableLeaves error:&error]; Do you mean that i need to add extra pair of key-value for each record in array 1? Something like this: nameOfThearray - array1 ? UPDATE: When i try to add extra pair of key-value to array1 it breaks with exception: mutating method sent to immutable object – Bobby Redjeans Feb 11 '14 at 15:09
Not need, could (I would). You need to change the JSON options to `NSJSONReadingMutableContainers | NSJSONReadingMutableLeaves` – Wain Feb 11 '14 at 15:10

score 1 · Answer 2 · edited May 23 '17 at 10:33

1

Combine all the arrays into one array.

NSMutableArray *all = [firstArray mutableCopy]
[all addObjectsFromArray:secondArray];
... add 3rd, 4th

Then you can sort that 'all' array. Have a look at How to sort NSArray of objects based on one attribute for an example of sorting the array.

edited May 23 '17 at 10:33

Community

1
1

answered Feb 11 '14 at 14:34

Graham Perks

23,007
8
61
83

Array of array Objective-C

2 Answers2