实例方法
prefix(_:)
返回一个子序列,最长为指定的最大长度,包含集合的初始元素。
声明
func prefix(_ maxLength: Int) -> Self.SubSequence
返回值
从此集合开头开始的子序列,最多包含 maxLength
个元素。
参数
maxLength
要返回的最大元素数。
maxLength
必须大于或等于零。
详述
如果最大长度超过集合中元素的数量,则结果包含集合中的所有元素。
let numbers = [1, 2, 3, 4, 5]
print(numbers.prefix(2))
// Prints "[1, 2]"
print(numbers.prefix(10))
// Prints "[1, 2, 3, 4, 5]"
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 prefix(_:)。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。