字符串截取演练

原始字符串

Swift 5.1 斯威夫特

想要结果 截取前部)

Swift 5

• 方式一

let str: String = "Swift 5.1 斯威夫特"
let startIdx = str.startIndex

let index = str.index(startIdx, offsetBy: 7)
let subStr: String = String(str.prefix(upTo: index))

• 方式二

let str: String = "Swift 5.1 斯威夫特"
let startIdx = str.startIndex

let subStr: String = String(str.prefix(7))