Question

I am attempting to use this array cleaning method, and there seems to be an error. I can’t spot it, I know the array goes in with 3116 items, comes out with 3116 (and I know for a fact there are three duplicates.

Please advice, thanks!

-(NSArray*) removeDuplicates:(NSArray*)inputArray{
NSMutableArray *arrayToClean = [NSMutableArray arrayWithArray:inputArray];
for (int i =0; i<[arrayToClean count]; i++) {

    for (int j=(i+1); j < [arrayToClean count]; j++) {
        if ([[arrayToClean objectAtIndex:i] isEqual:[arrayToClean
                                                     objectAtIndex:j]]) {
            [arrayToClean removeObjectAtIndex:j];
            j--;

        }

    }
}
NSArray *arrayToReturn = [NSArray arrayWithArray:arrayToClean];
return arrayToReturn;

}

Answer 1

NSSet will make this a lot easier:

-(NSArray *)removeDuplicates:(NSArray *)inputArray {
    NSSet *unique = [NSSet setWithArray:inputArray];

    return [unique allObjects];
}

Please note that a set has no guaranteed order. If you need the objects in the array to be in a specific order then you should sort the resulting array as needed.

It may also be appropriate to use an NSSet instead of the original array, then you don’t need to worry about duplicates at all. But this depends on the other needs of your array.