removing duplicates from array in objective c

Question

I have an array with custom objects. Each array item has a field named "name". Now I want to remove duplicate entries based on this name value.

How should I go about achieving this.

Thanks in advance.

Answer 1

You might have to actually write this filtering method yourself:

@interface NSArray (CustomFiltering)
@end

@implementation NSArray (CustomFiltering) 

- (NSArray *) filterObjectsByKey:(NSString *) key {
   NSMutableSet *tempValues = [[NSMutableSet alloc] init];
   NSMutableArray *ret = [NSMutableArray array];
   for(id obj in self) {
       if(! [tempValues containsObject:[obj valueForKey:key]]) {
            [tempValues addObject:[obj valueForKey:key]];
            [ret addObject:obj];
       }
   }
   [tempValues release];
   return ret;
}

@end

Answer 2

I do not know of any standard way to to do this provided by the frameworks. So you will have to do it in code. Something like this should be doable:

NSArray* originalArray = ... // However you fetch it
NSMutableSet* existingNames = [NSMutableSet set];
NSMutableArray* filteredArray = [NSMutableArray array];
for (id object in originalArray) {
   if (![existingNames containsObject:[object name]]) {
      [existingNames addObject:[object name]];
      [filteredArray addObject:object];
   }
}