NSPredicate 'OR' filtering based on an NSArray of keys - objective-c

Question

Consider the following NSArray:
NSArray *dataSet = [[NSArray alloc] initWithObjects:
[NSDictionary dictionaryWithObjectsAndKeys:#"abc", #"key1", #"def", #"key2", #"hij", #"key3", nil],
[NSDictionary dictionaryWithObjectsAndKeys:#"klm", #"key1", #"nop", #"key2", nil],
[NSDictionary dictionaryWithObjectsAndKeys:#"qrs", #"key2", #"tuv", #"key4", nil],
[NSDictionary dictionaryWithObjectsAndKeys:#"wxy", #"key3", nil],
nil];
I am able to filter this array to find dictionary objects that contain the key key1
// Filter our dataSet to only contain dictionary objects with a key of 'key1'
NSString *key = #"key1";
NSPredicate *key1Predicate = [NSPredicate predicateWithFormat:#"%# IN self.#allKeys", key];
NSArray *filteretSet1 = [dataSet filteredArrayUsingPredicate:key1Predicate];
NSLog(#"filteretSet1: %#",filteretSet1);
Which appropriately returns:
filteretSet1: (
{
key1 = abc;
key2 = def;
key3 = hij;
},
{
key1 = klm;
key2 = nop;
}
)
Now, I am wanting to filter the dataSet for dictionary objects containing ANY of the keys in an NSArray.
For example, using the array: NSArray *keySet = [NSArray arrayWithObjects:#"key1", #"key3", nil]; I want to create a predicate that returns and array of any dictionary objects that contain either 'key1' or 'key3' (ie. in this example all dictionary objects would be returned except for the third object - as it does not contain either 'key1' or 'key3').
Any ideas on how I would achieve this? Would I have to use a compound predicate?

Answer 1

The ANY operator of NSPredicate covers this:
NSSet *keys = [NSSet setWithObjects:#"key1", #"key3", nil];
NSPredicate *key1Predicate = [NSPredicate predicateWithFormat:#"any self.#allKeys in %#", keys];

Answer 2

Do this:
NSString *key = #"key1";
NSString *key1 = #"key3";
NSPredicate *key1Predicate = [NSPredicate predicateWithFormat:#"%# IN self.#allKeys OR %# IN self.#allKeys",key,key1];
NSArray *filteretSet1 = [dataSet filteredArrayUsingPredicate:key1Predicate];
NSLog(#"filteretSet1: %#",filteretSet1);
Works perfectly for me. Hope Helpful

Answer 3

Altough the question has been answered, you could also use block for more granularity:
NSArray *filter = [NSArray arrayWithObjects:#"key1", #"key3",nil];
NSPredicate *filterBlock = [NSPredicate predicateWithBlock: ^BOOL(id obj, NSDictionary *bind){
NSDictionary *data = (NSDictionary*)obj;
// use 'filter' and implement your logic and return YES or NO
}];
[dataSet filteredArrayUsingPredicate:filterBlock];
That could be rearranged as you want, maybe within its own method.