Returns the index of an object in the array that passes a test in a given block for a given set of enumeration options.
SDKs
- iOS 4.0+
- macOS 10.6+
- tvOS 9.0+
- watchOS 2.0+
Framework
- Foundation
Declaration
func indexOfObject(options opts: NSEnumerationParameters
optsA bit mask that specifies the options for the enumeration (whether it should be performed concurrently and whether it should be performed in reverse order).
predicateThe 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
trueto stop further enumeration of the array. If a block stops further enumeration, that block continues to run until it’s finished. When theNSEnumerationenumeration option is specified, enumeration stops after all of the currently running blocks finish. TheConcurrent stopargument is an out-only argument. You should only ever set this Boolean totruewithin the block.
The block returns a Boolean value that indicates whether
objpassed the test.
Return Value
The index whose corresponding value in the array passes the test specified by predicate and opts. If the opts bit mask specifies reverse order, then the last item that matches is returned. Otherwise, the index of the first matching object is returned. If no objects in the array pass the test, returns NSNot.
Discussion
By default, the enumeration starts with the first object and continues serially through the array to the last object. You can specify NSEnumeration and/or NSEnumeration as enumeration options to modify this behavior.