NSPredicate to search an array with any objects from a list | Obj C

Question

I have to sort/search an array of dictionaries based on an array of tag ids.

The web service send a list of articles which have tag ids like [1,2,3,5] for every article.

The user selects multiple tags from a list and there tag ids are stored in an array like [4,2,8,1]

** Now i have to compare the user selected tags with the article tags and if any tag in the 2 arrays match it is stored in a result array **

What should I use and How? NSPredicate or a NSSortdescriptor

In short i have to do something like this:

userTags = [4,6,2,1]
articleTags = [1,2,3,4,5]

if ANY [userTags] IN [articleTags] 
  [resultArr addObject:article]

Can you please elaborate more or provide the dummy NSDictionary ? — Mohshin Shah, Mar 06 '17 at 12:01
@TahaIshfaqBhutta In question you have told array of dictionary and in example you have shown both array of id? — Nirav D, Mar 06 '17 at 12:23
Please check this http://stackoverflow.com/questions/27810365/filter-nsarray-based-on-another-array-using-predicate — Saurabh Prajapati, Mar 06 '17 at 12:23
@NiravD The web service sends all the articles as json, so it is an array of dictionaries and every dictionary has an array of tags — Taha Ishfaq Bhutta, Mar 06 '17 at 12:29
Possible duplicate of [Searching NSArray of NSDictionary objects](http://stackoverflow.com/questions/5846271/searching-nsarray-of-nsdictionary-objects) — Sanman, Mar 06 '17 at 12:43

score 1 · Accepted Answer · answered Mar 06 '17 at 12:29

I believe you should use NSSet for your task instead of NSArrays. And check if sets intersect, e.g.:

NSSet *tags = [NSSet setWithArray:@[@1, @3, @5]];

NSSet *article1 = [NSSet setWithArray:@[@2, @4, @6]];
NSSet *article2 = [NSSet setWithArray:@[@2, @3, @4]];
NSLog(@"%d", [tags intersectsSet:article1]);
// 0
NSLog(@"%d", [tags intersectsSet:article2]);
// 1

score 0 · Answer 2 · answered Mar 06 '17 at 13:04

Mindaugas answer worked.

NSSet *selectedTagSet = [NSSet setWithArray:selectedTagIds];
NSMutableArray *result = [NSMutableArray array];

for (int i = 0; i < [self.responceArray count]; i++) {

    NSMutableDictionary *dict = [self.responceArray objectAtIndex:i];

    NSSet *tagSet = [NSSet setWithArray:[[dict objectForKey:@"seller"] objectForKey:@"tags"]];

    if ([tagSet intersectsSet:selectedTagSet])
    {
        [result addObject:[self.responceArray objectAtIndex:i]];
    }

}

NSPredicate to search an array with any objects from a list | Obj C

2 Answers2