Question

I have two NSArray, notiCloud and notiLoc, both with NSDictonary of the same structure. I need to know how to check how many NSDictionary are in both NSArray, for instance using the key @”id”.

Many thanks.

Answer 1

// Create arrays of the IDs only
NSArray *notiCloudIDs = [notiCloud valueForKey:@"id"];
NSArray *notiLocIDs = [notiLoc valueForKey:@"id"];

// Turn the arrays into sets and intersect the two sets
NSMutableSet *notiCloudIDsSet = [NSMutableSet setWithArray:notiCloudIDs];
NSMutableSet *notiLocIDsSet = [NSMutableSet setWithArray:notiLocIDs];
[notiCloudIDsSet intersectSet:notiLocIDsSet];

// The IDs that are now in notiCloudIDsSet have been present in both arrays
NSLog(@"Duplicate IDs: %@", notiCloudIDsSet);