# indexesOfObjects(at:options:passingTest:) Returns the indexes, from a given set of indexes, of objects in the array that pass a test in a given block for a given set of enumeration options. ``` func indexesOfObjects(at s: IndexSet, options opts: NSEnumerationOptions = [], passingTest predicate: (Any, Int, UnsafeMutablePointer) -> Bool) -> IndexSet ``` ## Parameters `s` The indexes of the objects over which to enumerate. `opts` A bit mask that specifies the options for the enumeration (whether it should be performed concurrently and whether it should be performed in reverse order). `predicate` The block to apply to elements in the array. The block takes three arguments: - obj: The element in the array. - idx: The index of the element in the array. - stop: A reference to a Boolean value. The block can set the value to to stop further enumeration of the array. If a block stops further enumeration, that block continues to run until it’s finished. When the `NSEnumerationConcurrent` enumeration option is specified, enumeration stops after all of the currently running blocks finish. The `stop` argument is an out-only argument. You should only ever set this Boolean to within the block. The block returns a Boolean value that indicates whether `obj` passed the test. ## Return Value The indexes whose corresponding values in the array pass the test specified by `predicate`. If no objects in the array pass the test, returns an empty index set. ## Discussion By default, the enumeration starts with the first object and continues serially through the array to the last element specified by `indexSet`. You can specify `NSEnumerationConcurrent` and/or `NSEnumerationReverse` as enumeration options to modify this behavior. > Important: > If the block parameter or the `indexSet` is `nil` this method will raise an exception. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)