实例方法
last(where:)
返回满足给定谓词的序列的最后一个元素。
声明
func last(where predicate: (Self.Element) throws -> Bool) rethrows -> Self.Element?
返回值
满足 predicate
的序列的最后一个元素,如果没有满足 predicate
的元素,则为 nil
。
参数
predicate
一个闭包,它将序列的一个元素作为其参数,并返回一个布尔值,指示该元素是否匹配。
详述
此示例使用 last(where:)
方法查找整数数组中的最后一个负数:
let numbers = [3, 7, 4, -2, 9, -6, 10, 1]
if let lastNegative = numbers.last(where: { $0 < 0 }) {
print("The last negative number is \(lastNegative).")
}
// Prints "The last negative number is -6."
可用版本
iOS 8.0+, iPadOS 8.0+, macOS 10.10+, Mac Catalyst 13.0+, tvOS 9.0+, watchOS 2.0+
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