How to Predicate through Nested Arrays with Keys

ios, nspredicate

Solution

"artist" is an array, therefore you have to use "ANY" in the predicate:

[NSPredicate predicateWithFormat:@"ANY %K.%K CONTAINS[c] %@",
              @"artist",@"name",searchText];

Note that instead of building the "union" of the search results manually, you can use a "compound predicate":

NSPredicate *predicate = [NSCompoundPredicate orPredicateWithSubpredicates:
                          @[predicateEventsByName, predicateEventsByArtistName]];
self.filteredEventsArray = [self.eventsArray filteredArrayUsingPredicate:predicate];

Problem

I have an array called `self.eventsArray` which looks like this: ``` [ { "artist": [ { "artist_name": "Dillon Francis", "name": "Dillon Francis", }, { "artist_name": "Major Lazer", "name": "Major Lazer", }, { "artist_name": "Flosstradamus ", "name": "Flosstradamus", } ], "name": "Mad Decent Block Party NYC", }, { "artist": [ { "artist_name": "Ryan Raddon", "name": "Kaskade", } ], "name": "Kaskade Atmosphere Tour NYC", }, ] ``` I have been trying to filter it by using `NSPredicate` two times. When the user searches, it needs to be filtered by either name (in the artist array) or name (in the top-level array). ``` NSPredicate *predicateEventsByName = [NSPredicate predicateWithFormat:@"SELF.%K contains[c] %@",@"name",searchText]; NSPredicate *predicateEventsByArtistName = [NSPredicate predicateWithFormat:@"SELF.%K.%K contains[c] %@",@"artist",@"name",searchText]; NSMutableArray *unfilteredEventsArray = [[NSMutableArray alloc] initWithCapacity:0]; unfilteredEventsArray = [NSMutableArray arrayWithArray:[self.eventsArray filteredArrayUsingPredicate:predicateEventsByName]]; [unfilteredEventsArray addObjectsFromArray:[self.eventsArray filteredArrayUsingPredicate:predicateEventsByArtistName]]; [self.filteredEventsArray addObjectsFromArray:[[NSSet setWithArray:unfilteredEventsArray] allObjects]]; ``` Using this code, `self.filteredEventsArray` will be populated with any search term matching the top-level `"name"`. It won't give any search results for the nested artist `"name"`. I suspect the reason why it won't search through the nested array is because of this line: ``` NSPredicate *predicateEventsByArtistName = [NSPredicate predicateWithFormat:@"SELF.%K.%K contains[c] %@",@"artist",@"name",searchText]; ``` but I can't figure out how to change the `predicateWithFormat:` to make it search through the nested array.

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