實例方法
first
firstIndex(of:)
返回指定值出現在集合中的第一個索引。
聲明
func firstIndex(of element: Self.Element) -> Self.Index?
當
Element
符合 Equatable
時可用。返回值
找到element
的第一個索引。如果在集合中找不到 element
,則返回 nil
。
參數
element
要在集合中搜索的元素。
詳述
使用firstIndex(of:)
查找集合中特定元素的位置後,您可以使用它通過下標來訪問該元素。此示例說明如何修改學生數組中的一個姓名。
var students = ["Ben", "Ivy", "Jordell", "Maxime"]
if let i = students.firstIndex(of: "Maxime") {
students[i] = "Max"
}
print(students)
// Prints "["Ben", "Ivy", "Jordell", "Max"]"
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 UnsafeMutableBufferPointer firstIndex(of:)。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。