實例屬性
first
集合的第一個元素。
聲明
var first: Self.Element? { get }
詳述
如果集合為空,則此屬性的值為 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+
相關用法
- Swift String.UnicodeScalarView first(where:)用法及代碼示例
- Swift String.UnicodeScalarView firstIndex(of:)用法及代碼示例
- Swift String.UnicodeScalarView firstIndex(where:)用法及代碼示例
- Swift String.UnicodeScalarView filter(_:)用法及代碼示例
- Swift String.UnicodeScalarView flatMap(_:)用法及代碼示例
- Swift String.UnicodeScalarView forEach(_:)用法及代碼示例
- Swift String.UnicodeScalarView min(by:)用法及代碼示例
- Swift String.UnicodeScalarView lastIndex(of:)用法及代碼示例
- Swift String.UnicodeScalarView replaceSubrange(_:with:)用法及代碼示例
- Swift String.UnicodeScalarView compactMap(_:)用法及代碼示例
- Swift String.UnicodeScalarView sorted()用法及代碼示例
- Swift String.UnicodeScalarView split(separator:maxSplits:omittingEmptySubsequences:)用法及代碼示例
- Swift String.UnicodeScalarView shuffled(using:)用法及代碼示例
- Swift String.UnicodeScalarView removeFirst(_:)用法及代碼示例
- Swift String.UnicodeScalarView starts(with:)用法及代碼示例
- Swift String.UnicodeScalarView elementsEqual(_:)用法及代碼示例
- Swift String.UnicodeScalarView remove(at:)用法及代碼示例
- Swift String.UnicodeScalarView lexicographicallyPrecedes(_:)用法及代碼示例
- Swift String.UnicodeScalarView append(_:)用法及代碼示例
- Swift String.UnicodeScalarView contains(_:)用法及代碼示例
- Swift String.UnicodeScalarView enumerated()用法及代碼示例
- Swift String.UnicodeScalarView insert(_:at:)用法及代碼示例
- Swift String.UnicodeScalarView last用法及代碼示例
- Swift String.UnicodeScalarView reversed()用法及代碼示例
- Swift String.UnicodeScalarView shuffled()用法及代碼示例
注:本文由純淨天空篩選整理自apple.com大神的英文原創作品 String.UnicodeScalarView first。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。