self.iter().is_sorted_by_key(f)
}
- /// Returns index of partition point according to the given predicate,
- /// such that all those that return true precede the index and
- /// such that all those that return false succeed the index.
+ /// Returns the index of the partition point according to the given predicate
+ // (the index of the first element of the second partition).
///
- /// The slice must be partitioned
- /// so that all elements where the predicate returns true
- /// precede the elements where the predicate returns false.
+ /// The slice is assumed to be partitioned according to the given predicate.
+ /// This means that all elements for which the predicate returns true are at the start of the slice
+ /// and all elements for which the predicate returns false are at the end.
+ /// For example, [7, 15, 3, 5, 4, 12, 6] is a partitioned under the predicate x % 2 != 0
+ /// (all odd numbers are at the start, all even at the end).
+ ///
+ /// If this slice is not partitioned, the returned result is unspecified and meaningless,
+ /// as this method performs a kind of binary search.
///
/// # Examples
///