Merging arrays having multiple values to form one array/dictionary

Question

I have an array with data from server. I can't change the server's response.

{
    maximum = 30;
    minimum = 1;
    name = "Layer 1";
},
    {
    maximum = 60;
    minimum = 45;
    name = "Layer 1";
},
    {
    maximum = 60;
    minimum = 45;
    name = "Layer 2";
}

I have 3 objects in this array. 2 of them are with the same name but with different minimum and maximum values. I want to create an array which won't have duplications, so for example I'll have 2 object in my array, "Layer 1", "Layer 2". Layer 1 will have the 2 minimum values, and maximum values.

How it should look like:

{

    name = "Layer 1"; value = [{maximum = 30;
    minimum = 1},{ maximum = 60;
    minimum = 45}];
},
    {
    maximum = 60;
    minimum = 45;
    name = "Layer 2";
}

I have tried to check if the "name" of the object at index "i" is equals to the "name" of the object at index "i+1" but it crahses, it says "beyond bounds (2):

rows = [mivne_shichva count];

         NSMutableArray *layers = [[NSMutableArray alloc]init];
        NSMutableDictionary *layer = [[NSMutableDictionary alloc]init];

        for (int i = 0; i<rows; i++) {
            if ([[[mivne_shichva objectAtIndex:i]valueForKey:@"name"] isEqualToString:[[mivne_shichva objectAtIndex:i+1]valueForKey:@"name"]]) {
                NSLog(@"name equals to name in i+1");
            }
            [layer setValue:[[mivne_shichva objectAtIndex:i]valueForKey:@"name"] forKey:@"name"];
            [layer setValue:[[mivne_shichva objectAtIndex:i]valueForKey:@"minimum"] forKey:@"minimum"];
            [layer setValue:[[mivne_shichva objectAtIndex:i]valueForKey:@"maximum"] forKey:@"maximum"];

            [layers addObject:layer];

            NSLog(@"layers :::: %@",layers);            
        }

I'm sure you tried something, but it did not work. Would you mind sharing your latest attempt that was closest to your goal? We'll help you make it work. — Sergey Kalinichenko
– Sergey Kalinichenko, Commented Dec 18, 2012 at 11:23
Yeah, I have tried to check if the object at index "i" is equals to object at index i+1 but it crashes... says it beyond bounds (2)... I have added my code to my question — Yosi Dahan
– Yosi Dahan, Commented Dec 18, 2012 at 11:26
That's because your loop needs to go up to rows - 1, not up to rows, when you plan to use i + 1 as an index expression. — Sergey Kalinichenko
– Sergey Kalinichenko, Commented Dec 18, 2012 at 11:34
is this structure acceptable to make it generic ? { name = "Layer 1"; value = [ {maximum = 30, minimum = 1}, {maximum = 60, minimum = 45} ]; }, { name = "Layer 1"; value = [ {maximum = 60, minimum = 45} ]; } — Anoop Vaidya
– Anoop Vaidya, Commented Dec 18, 2012 at 11:34

Anoop Vaidya · Accepted Answer · 2012-12-18 13:42:47Z

Check this one, The Logic is as

The final result will be in a 'dictionary'. The 'dictionary' key contains the name as 'Layer 1' The 'dictionary' value contains an 'array'. The 'array' contains objects of 'MinMax'.

The MinMax class:

@interface MinMax : NSObject

@property(strong)NSString *minimum;
@property(strong)NSString *maximum;

@end

The MyClass class:

@interface MyClass : NSObject

@property(strong) NSString *name;
@property(strong) NSString *minimum;
@property(strong) NSString *maximum;

@end

And the demo implementation:

- (id)init
{
    self = [super init];
    if (self) {
        _finalDict=[NSMutableDictionary new];

        MyClass *obj1=[MyClass new];
        obj1.name=@"Layer 1";
        obj1.minimum=@"1";
        obj1.maximum=@"30";

        MyClass *obj2=[MyClass new];
        obj2.name=@"Layer 1";
        obj2.minimum=@"45";
        obj2.maximum=@"60";

        MyClass *obj3=[MyClass new];
        obj3.name=@"Layer 2";
        obj3.minimum=@"45";
        obj3.maximum=@"60";

        _fromServerArrays=[[NSMutableArray alloc]initWithObjects:obj1, obj2, obj3, nil];

    }
    return self;
}

- (void)applicationDidFinishLaunching:(NSNotification *)aNotification{

    for (MyClass *obj in _fromServerArrays) {
        NSLog(@"From server  : %@, %@, %@", obj.name, obj.minimum, obj.maximum);
    }


    for (MyClass *myClassObj in _fromServerArrays) {
        MinMax *mmObj=[MinMax new];
        mmObj.minimum=myClassObj.minimum;
        mmObj.maximum=myClassObj.maximum;

        if ([_finalDict objectForKey:myClassObj.name]) {
            NSMutableArray *getArray=[_finalDict objectForKey:myClassObj.name];
            [getArray addObject:mmObj];
        }
        else{
            NSMutableArray *array=[NSMutableArray new];
            [array addObject:mmObj];
            [_finalDict setObject:array forKey:myClassObj.name];
        }
    }


    for (NSDictionary *dict in _finalDict) {
        NSLog(@"%@",dict);
        for (MinMax *mmObj in [_finalDict objectForKey:dict]) {
            NSLog(@"%@, %@", mmObj.minimum, mmObj.maximum);
        }
    }
}

Output:

From server  : Layer 1, 1, 30
From server  : Layer 1, 45, 60
From server  : Layer 2, 45, 60
Layer 1
1, 30
45, 60
Layer 2
45, 60

I have tried this kind of algo already... i don't know how to implement it as a working code... :-/

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