Question

i have an array of dictionary objects with repeated objects, i need to make another array with no repeated objects with another key that represents the number of times that object was repeated.

Example:

object A (key1, key2)
object B (key1, key2)
object C (key1, key2)
object B (key1, key2)
object B (key1, key2)

Result,with new dictionary array:

object A (key1, key2, count(1))
object B (key1, key2, count(3))
object C (key1, key2, count(1))

Im having a hard time since im new to NSDictionary objects, the code so far:

for(int j = 1; j < [objects count]; j++)
{
    for(int k = j+1;k < [objects count]-j;k++)
    {
        NSMutableDictionary *item1 = [objects objectAtIndex:j];
        NSMutableDictionary *item2 = [objects objectAtIndex:k];

        NSString *str1 = [item1 valueForKey:@"setArrivalAirportOrCode"];
        NSString *str2 = [item2 valueForKey:@"setArrivalAirportOrCode"];

        NSLog(@"%@==%@ ???",str1,str2);
        if([str1 isEqualToString:str2])
            NSLog(@"%@==%@",str1,str2);
    }
}

Im trying to count the objects and copy them to a new array, i am not sure if i am going in the right direction, sorry for my poor English and please don’t down-vote, just ask me anything i am always online.

Thanks in Advance!

Answer 1

Create a NSCountedSet and it will take care of the counting for you.

In this example, I used NSString objects but it can be done with any type of object:

NSString        *stringA    = @"stringA";
NSString        *stringB    = @"stringB";
NSString        *stringC    = @"stringC";
NSArray         *array      = [NSArray arrayWithObjects:stringA, stringB, stringC, stringB, stringB, nil];
NSCountedSet    *countedSet = [NSCountedSet setWithArray:array];

NSLog(@"%@", countedSet);
// Results:  <NSCountedSet: 0x6b35790> (stringA [1], stringB [3], stringC [1])

In order to get the count, you use:

NSLog(@"%d", [countedSet countForObject:stringB]);
// Result:  3

In order to get the results in a separate array (note that you lose the counts, so use the counted set for that), use:

NSArray *array2 = [countedSet allObjects];
NSLog(@"%@", array2);
/*
 * (
 * stringA,
 * stringB,
 * stringC
 * )
 */