How to avoid duplicated objects being inserted in NSArray?

Question

Well, I am having problems with an nsarray that it is adding duplicate objects from an nsdictionary.

The situation is this: I have a plist file with an array of dictionaries. Each dictionary have the key being 'codigo' and 'var'.

What I did is I am checking each 'var' value if it is < 0 and if it is 'codigo' and 'var' will get a color using NSAttributedStrings.

The problem comes when I iterate through the array and add the evaluated 'var' into the new array. I am getting duplicated objects in the final array.

EDIT: Solution derived from xlc0212's answer and help through chat:

_timer = [NSTimer scheduledTimerWithTimeInterval:0.020 target:self
                                        selector:@selector(time:) userInfo:nil repeats:YES];

NSDictionary *redAttrs    = @{NSForegroundColorAttributeName:[UIColor redColor]};
NSDictionary *greenAttrs  = @{NSForegroundColorAttributeName:[UIColor colorWithRed:0.118 green:0.506 blue:0.000 alpha:1.000]};
NSDictionary *orangeAttrs = @{NSForegroundColorAttributeName:[UIColor orangeColor]};

NSString *stringUm = @"";
NSString *stringDois = @"";
NSString *stringTres = @"";


arrayAtivos = [[NSMutableOrderedSet alloc] init];
NSDictionary *item = [[NSDictionary alloc]init];

for (item in array){

    NSString *alfa = [item objectForKey:@"var"];

    float fltNumber = [alfa floatValue];

    if (fltNumber < 0) {
        stringUm = [NSString stringWithFormat:@"%@ %.2f  ",[item objectForKey:@"codigo"], fltNumber];
        int strLength = [stringUm length];
        attStr = [[NSMutableAttributedString alloc] initWithString:stringUm];
        [attStr setAttributes:redAttrs range:NSMakeRange(0,strLength)];

    } else if (fltNumber > 0 ) {
        stringDois = [NSString stringWithFormat:@"%@ %.2f  ",[item objectForKey:@"codigo"], fltNumber];
        int strLength = [stringDois length];
        attStr = [[NSMutableAttributedString alloc] initWithString:stringDois];
        [attStr setAttributes:greenAttrs range:NSMakeRange(0,strLength)];

    } else if (fltNumber == 0) {
        stringTres = [NSString stringWithFormat:@"%@ %.2f  ",[item objectForKey:@"codigo"], fltNumber];
        int strLength = [stringTres length];
        attStr = [[NSMutableAttributedString alloc] initWithString:stringTres];
        [attStr setAttributes:orangeAttrs range:NSMakeRange(0,strLength)];
    }

    [arrayAtivos addObject:attStr];

}

Answer 1

NSMutableOrderedSet is what you want. Just replace NSMutableArray with NSMutableOrderedSet and done.

If you want to filter the array, use this

NSArray *array = // your array
NSMutableArray *filteredArray = [[[NSOrderedSet alloc] initWithArray: array] mutableCopy];

---

Replace

arrayAtivos = [NSMutableArray new];

with this

arrayAtivos = [[NSMutableOrderedSet alloc] init];

and change the type of arrayAtivos to NSMutableOrderedSet