Reorders the elements of the collection such that all the elements that match the given predicate are after all the elements that don’t match.
- iOS 7.0+
- macOS 10.9+
- Mac Catalyst 13.0+
- tvOS 9.0+
- watchOS 2.0+
- Xcode 10.0+
A predicate used to partition the collection. All elements satisfying this predicate are ordered after all elements not satisfying it.
The index of the first element in the reordered collection that matches
belongs. If no elements in the collection match
belongs, the returned index is equal to the collection’s
After partitioning a collection, there is a pivot index
p where no element before
p satisfies the
belongs predicate and every element at or after
In the following example, an array of numbers is partitioned by a predicate that matches elements greater than 30.
numbers array is now arranged in two partitions. The first partition,
numbers[..<p], is made up of the elements that are not greater than 30. The second partition,
numbers[p...], is made up of the elements that are greater than 30.
Complexity: O(n), where n is the length of the collection.