无法对数组进行排序：“对成员'<'的引用不明确”

Question

extension Array where Element: Numeric {
    func closest(to givenValue: Element) -> Element {
        let sorted = self.sorted(by: <)

        let over = sorted.first(where: { $0 >= givenValue })!
        let under = sorted.last(where: { $0 <= givenValue })!

        let diffOver = over - givenValue
        let diffUnder = givenValue - under

        return (diffOver < diffUnder) ? over : under
    }
}

在此示例代码的第3行中，Xcode给出了我无法理解的错误消息Ambiguous reference to member '<'以及以下列表：

我应该在这里做什么？我只希望此数组得到排序。

Answer 1

您必须声明Element是Comparable：

extension Array where Element: Numeric & Comparable {