I am stuck in one problem.I am not able to get full object from an array.I have array of class objects and i need to get list of unique elements.i write this code
[objects valueForKeyPath:@"@distinctUnionOfObjects.B1_UM"]
But the problem is my class have many elements and i get list of only unique B1_UM,instead i need list of objects where B1_UM is unique
I think you have to do that "manually" by enumerating over all objects, and using a set to keep track of which keys have already been added. Something like this (untested):
NSMutableSet *b1ums = [NSMutableSet set];
NSMutableArray *uniqueObjects = [NSMutableArray array];
for (MyClass *obj in objects) {
if (![b1ums containsObject:obj.b1_um]) {
[b1ums addObject:obj.b1_um]; // remember key
[uniqueObjects addObject:obj]; // add object
}
}
Theoretically, you could override isEqual and hash in your custom class
to consider two objects identical if the b1_um property is equal.
But that might be a bit overkill.
Edit: I had not noticed that your question is tagged with [core-data].
For managed objects, an alternative approach would be possible: Execute a fetch request
with NSDictionaryResultType and set propertiesToGroupBy to the "b1_um" attribute.
Then you can pick one object from each group in the returned result.
NSSet.