Is there an equivalent to Smalltalk’s #copyWithout: in Cocoa’s collection classes?

Question

In Smalltalk i am used to make a copy of a collection without an undesired element like this:

myCollection copyWithout: undesiredObject

which answers a copy of the receiver that does not contain any elements equal to undesiredObject.

Is there an equivalent in Cocoa?
If not, what is the best way to achieve such a copy?
I am especially interested in copying instances of NSSet.

Answer 1

There is no direct equivalent in the Cocoa Foundation classes.

Possible method #1:

NSSet *withoutUndesiredObject = [myCollection objectsPassingTest:^BOOL(id obj, BOOL *stop) {
    return ![obj isEqualTo:undesiredObject];
}];

Possible method #2:

NSMutableSet *withoutUndesiredObject = [myCollection mutableCopy];
[withoutUndesiredObject removeObject:undesiredObject];

Similar methods exist also for the other collection classes NSArray and NSDictionary.