Merge the same objects inside array IOS

Edit: Oops, I missed your count requirement.

Edit 2: And the fact that you wanted to mutate the given array rather the build a new one.

Depends on what you mean by distinct but since it looks like you mean to compare the contents and not the references, you should build a new array so that if the comparison is true you increment the count and otherwise you add the object.

Mutate existing array

Disclaimer: probably not my best work here.

I would appreciate if someone could suggest how to improve this because I am pretty sure it is not the best way to do this and may not even work (don't have access to an Obj-C compiler at the moment).

Foo objectA = [Foo new];
objectA.Bar = @"Bar";
Foo objectB = [Foo new];
objectB.Bar = @"Bar";
Foo objectC = [Foo new];
objectC.Bar = @"Not Bar";

NSMutableArray *array = @[objectA, objectB, objectC];

NSMutableDictionary *countDictionary = [[NSMutableDictionary alloc] init];

for (Foo *foo in [array copy])
{
    bool found = false;

    for (Foo *key in countDictionary)
    {
        if ([key isEqualTo:foo])
        {
            NSNumber *currentCount = [countDictionary objectForKey:key];
            int currentIntCount = [currentCount intValue];
            currentIntCount++;
            [countDictionary setObject:[NSNumber numberWithInt:currentIntCount] forKey:key];

            [array removeObject:key];

            found = true;

            break;
        }

        if (!found)
            [countDictionary setObject:[NSNumber numberWithInt:1] forKey:foo];
    }
}

for (Foo *realFoo in array)
{
    NSNumber *countNumber = [countDictionary objectForKey:realFoo];
    int countInt = [countNumber intValue];

    realFoo.Count = countInt;
}

Build new array

Foo objectA = [Foo new];
objectA.Bar = @"Bar";
Foo objectB = [Foo new];
objectB.Bar = @"Bar";

NSMutableArray *array = @[objectA, objectB];
NSMutableArray *distinct = [[NSMutableArray alloc] init];

for (Foo *f in array)
{
    bool found = false;
    for (Foo *d in distinct)
    {
        if ([d isEqualTo:f])
        {               
            found = true;
            d.Count++;
        }
        break;
    }

    if (!found)
        [distinct addObject:f];
}

And of course you would have to define an equality comparer for Foos, in this case for instance

-(bool) isEqualTo:(Foo *)nFoo
{
    bool isEqual = false;

    if ([self.Bar isEqualToString:nFoo.Bar])
         isEqual = true;

    return isEqual;
}

Having not dealt with Objective C in a while I should say that there may be some best-practices as to implementing equality comparison instead of rolling your own completely like this example