Return Value 戻り値
A sequence starting at the beginning of this sequence with at most max elements.
Instance Method
インスタンスメソッド
prefix(_:)
Returns a sequence, up to the specified maximum length, containing the initial elements of the sequence.
Availability 有効性
- iOS 13.0+
- iPadOS 13.0+
- macOS 10.15+
- Mac Catalyst 13.0+
- tvOS 13.0+
- watchOS 6.0+
Technology
- Swift
UI
Declaration 宣言
func prefix(_ maxLength: Int) -> PrefixSequence <Self>Parameters パラメータ
maxLengthThe maximum number of elements to return. 返される要素の最大限の数。 The value of
maxmust be greater than or equal to zero.Length
Discussion 議論
If the maximum length exceeds the number of elements in the sequence, the result contains all the elements in the sequence.
let numbers = [1, 2, 3, 4, 5]
print(numbers.prefix(2))
// Prints "[1, 2]"
print(numbers.prefix(10))
// Prints "[1, 2, 3, 4, 5]"