实例属性
first
集合的第一个元素。
声明
var first: Self.Element? { get }
详述
如果集合为空,则此属性的值为 nil
。
let numbers = [10, 20, 30, 40, 50]
if let firstNumber = numbers.first {
print(firstNumber)
}
// Prints "10"
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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注:本文由纯净天空筛选整理自apple.com大神的英文原创作品 UnsafeMutableRawBufferPointer first。非经特殊声明,原始代码版权归原作者所有,本译文未经允许或授权,请勿转载或复制。