我已迁移到Swift 3.0,现在我在这一行上收到错误:
let lastFourDigits = (accountNumber as NSString).substringWithRange(accountNumber.endIndex.advancedBy(-4)..<accountNumber.endIndex)
No '..<' candidates produce the expected contextual result type 'NSRange' (aka '_NSRange')
。我在这里做错了什么?
答案 0 :(得分:2)
索引操作的语法已更改(请参阅Get nth character of a string in Swift programming language和完整的基本原理:Swift Evolution 0065):
let accountNumber = "XX0000000000000000001234"
let lastFourDigits = accountNumber[accountNumber.index(accountNumber.endIndex, offsetBy: -4)..<accountNumber.endIndex]
print("Last 4: \(lastFourDigits)")
无需在Swift中使用NSString
或NSRange
。
更简单的语法也是:
let lastFourDigits = accountNumber.substring(from: accountNumber.index(accountNumber.endIndex, offsetBy: -4))