Using NSPredicate to search an array with an array

20
votes

I have an array of Card objects (NSObjects), each with a field called tags, which is an NSArray of NSStrings.

I would then like to split up the user's search term into an array called keywords of strings by componentsSeparatedByString, then use NSPredicate to filter my array of Cards based on which elements have tags containing at least 1 keyword in keywords.

I hope that's not too convoluted! I've tried using the NSPredicate IN clause to no avail. How should I do this?

2
objective-ciosnspredicate

2 Answers

60
votes

Considering array contains card Object. 

 NSArray *keyWordsList = [keywords componentSeparatedByString:@","];
 [array filteredArrayUsingPredicate:[NSPredicate predicateWithFormat:@"ANY %K IN %@",@"tags",keyWordsList]]

EDIT:

To search partially you can use LIKE operator. 

[array filteredArrayUsingPredicate:[NSPredicate predicateWithFormat:@"ANY %K LIKE[cd] %@",@"tags",[partialkeyWord stringByAppendingString:@"*"]]]
9
votes

Don't kill me if this isn't exactly right, but something like this will work.

NSArray* arrayOfCards = [NSArray array];
NSArray* keywords = [NSArray array];
NSPredicate* containsAKeyword = [NSPredicate predicateWithBlock: ^BOOL(id evaluatedObject, NSDictionary *bindings) {
    Card* card = (Card*)evaluatedObject;
    NSArray* tagArray = card.tags;
    for(NSString* tag in tagArray) {
       if( [keywords containsObject: tag] ) 
          return YES;
    }

    return NO;
}];

NSArray* result = [arrayOfCards filteredArrayUsingPredicate: containsAKeyword];