Question

I have app where data after pushing viewcontroller (multiple times) collects in the NSMutableArray

nextController.pathArray = self.pathArray;

How to prevent duplicating data from pathArray in nextController.pathArray?

Answer 1

Create a NSMutableSet and add your object there as well. Before adding items to your mutable array check first before you add it if it exist in the set. Where ever your adding your data should look something like this example:

if (![set containsObject:data])
{
   [set addObject:data];
   [self.pathArray addObject:data
}

If you aren’t concern about arrangement for you collection I would suggestion of using a NSMutableSet instead of NSMutableArray and converting it back to a mutable array when changing view controllers like so:

      nextController.pathArray = self.set.allObjects.mutableCopy;