CODEWITHSUNDEEP
iosobjective-cnsarraynspredicate
Piero
Piero

Reputation: 9273

Filter NSArray of NSNumber with NSArray of NSNumber with NSPredicate

I have this custom class:

@interface MyModel : NSObject

@property (nonatomic,strong) NSString *id_name;
@property (nonatomic,strong) NSArray *genres;

@end

The genres array is an array of NSNumbers. I fill another array with the MyModel object, for example:

MyModel *m = [[MyModel alloc] init];
m.id_name = @"2345";
m.genres = [NSArray arrayWithObjects:[NSNumber numberWithInt:3],[NSNumber numberWithInt:5],nil];

MyModel *m2 = [[MyModel alloc] init];
m2.id_name = @"259";
m2.genres = [NSArray arrayWithObjects:[NSNumber numberWithInt:7],[NSNumber numberWithInt:10],nil];

MyModel *m3 = [[MyModel alloc] init];
m3.id_name = @"25932as";
m3.genres = [NSArray arrayWithObjects:[NSNumber numberWithInt:7],[NSNumber numberWithInt:10],[NSNumber numberWithInt:15],nil];

myArray = [NSArray arrayWithObjects:m,m2,m3,nil];

Now I want to filter myArray such that the genres are contained within the elements of this array:

NSArray *a = [NSArray arrayWithObjects:[NSNumber numberWithInt:7],[NSNumber numberWithInt:10],nil];

So, myArray, after filtering, should contain the objects m2 and m3. Can I do this with NSPredicate? If so, how? Or is there another way?

Upvotes: 0

Views: 825

Answers (2)

Monolo
Monolo

Reputation: 18253

Martin R has provided an elegant answer, but if I understand your question correctly, you can also use a simpler predicate:

NSPredicate *allPred = [NSPredicate predicateWithFormat: @"ALL %@ IN genres", a];

NSArray *result = [myArray filteredArrayUsingPredicate: allPred];

This predicate will find MyModels that contain all of the genres included in your a array. In the case of your test data, that will be the two objects with ids 259 and 25932as.

Upvotes: 1

Martin R
Martin R

Reputation: 539715

To find the objects that have at least one genre in the given array a, use

[NSPredicate predicateWithFormat:@"ANY genres in %@", a];

To find the objects that have all genres in the given array, a SUBQUERY is needed:

[NSPredicate predicateWithFormat:@"SUBQUERY(genres, $g, $g IN %@).@count = %d", a, [a count]];

(The idea is to check if the number of genres that are in the given array is equal to the size of the array.)

Upvotes: 0

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