實例方法
prefix(_:)
返回一個序列,最長為指定的最大長度,包含序列的初始元素。
聲明
func prefix(_ maxLength: Int) -> PrefixSequence<Self>
返回值
從該序列的開頭開始的序列,最多包含 maxLength
個元素。
參數
maxLength
要返回的最大元素數。
maxLength
的值必須大於或等於零。
詳述
如果最大長度超過序列中元素的數量,則結果包含序列中的所有元素。
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:本文由純淨天空篩選整理自apple.com大神的英文原創作品 IteratorSequence prefix(_:)。非經特殊聲明,原始代碼版權歸原作者所有,本譯文未經允許或授權,請勿轉載或複製。